Chapter 17

four categories of variability:

Absent: Undetectable Minimal: Undetectable to ≤5 bpm Moderate: 6 to 25 bpm Marked: >25 bpm

Accuracy and internal fetal monitoring

Accuracy is the main advantage of using internal devices for EFM, but they are invasive, slightly increasing the risk for infection. Their use requires ruptured membranes and about 2 cm of cervical dilation.

VAS

Acoustic stimulation, or VAS, may be used by the nurse, physician, or nurse-midwife to supplement fetal scalp stimulation or if scalp stimulation is contraindicated. Because of its simplicity and noninvasive nature, VAS is common. A stimulator that uses a combination of sound and vibration is applied to the mother's lower abdomen, and it is turned on for up to 3 seconds. The reassuring response is the same as with fetal scalp stimulation: an acceleration in FHR of 15 bpm for 15 seconds or more. An absent response, however, does not necessarily mean that the fetus is hypoxic or in acidosis.

BOX 17-2 GUIDELINES FOR ASSESSMENT AND DOCUMENTATION OF FETAL HEART RATE AUSCULTATION FOR WOMEN AT LOW RISK

Active First-Stage Labor Every 15-30 min, just after a contraction Second-Stage Labor Every 5-15 min Other Times to Document Fetal Heart Rate • Before artificial rupture of the membranes; after rupture of the membranes, either artificially or spontaneously • Before and after ambulation • If contractions become too frequent or last too long, or if there is an inadequate interval between them • Before administration of oxytocin and when evaluating the dose for increase, maintenance, or decrease • Before administration of sedative medications or central nervous system depressants and at time of peak action • Before epidural analgesia is started and every 15 min for 1 hr after it is started

Maternal Cardiopulmonay Alterations

Actual or relative reductions in the mother's circulating blood volume reduce perfusion of the intervillous spaces with oxygenated maternal blood. Hemorrhage causes an actual decrease in her blood volume. Relative reductions in maternal circulating volume result from altered distribution of the blood volume without blood loss. For example, epidural block analgesia may result in vasodilation, which increases the capacity of the maternal vascular bed. However, the amount of blood available to fill the vessels is unchanged. Hypotension can result, reducing placental blood flow. Maternal hypertension may reduce blood flow to the placenta because of vasospasm and narrowing of the spiral arteries. A lowered oxygen level in the mother's blood reduces the amount available to the fetus. Maternal acid-base alterations, which often accompany respiratory abnormalities or diabetic ketoacidosis, may also compromise exchange in the placenta. A lower maternal oxygen tension may result from respiratory disorders, such as asthma or acute pulmonary infections, or from smoking.

Nursing Diagnosis

Deficient Knowledge of fetal monitoring.

SAFETY ALERT: Nursing Responses to Nonreassuring Fetal Heart Rate Patterns

1. Identify the cause of the nonreassuring pattern to plan appropriate interventions: •Evaluate characteristics of the pattern that are nonreassuring (late or variable decelerations, bradycardia or tachycardia, absent or minimal variability). Determine if combinations of nonreassuring characteristics exist (i.e., late decelerations with minimal variability). •Evaluate maternal vital signs to identify hypotension, hypertension, or fever that may contribute to the fetal response associated with a nonreassuring pattern. •If indicated, perform a vaginal examination to identify a prolapsed umbilical cord. Do not perform a vaginal examination if there is active vaginal bleeding, diagnosed placenta previa, preterm labor or preterm premature rupture of the membranes, or a high risk for infection. 2. Stop oxytocin or other uterine stimulants. A tocolytic such as terbutaline may be ordered. 3. Reposition the woman, avoiding the supine position, for patterns associated with cord compression. Repositioning often improves other nonreassuring patterns as well. 4. Increase the rate of infusion of a nonadditive intravenous fluid to expand the mother's blood volume and improve placental perfusion. 5. Administer oxygen by facemask at 8 to 10 L/min to increase maternal blood oxygen saturation, making more oxygen available to the fetus. Maternal pulse oximetry, available on many fetal monitors, allows ongoing assessment of maternal oxygen saturation and documentation on the strip if the information is crucial. 6. Consider starting continuous EFM with internal devices if no contraindication exists. 7. Notify the physician or nurse-midwife as soon as possible, or ask another nurse to notify. Report and document the following: •The pattern that was identified •Nursing interventions taken in response to the pattern •The fetal response after nursing interventions •The response of the physician or nurse-midwife (orders, other response) 8. If the nonreassuring pattern is severe, other staff members should be alerted to the possibility of immediate delivery (usually cesarean birth, unless operative vaginal birth is possible and quicker). Birth preparation should include staff prepared for neonatal resuscitation.

Fetal Heart Rate Monitoring with an Ultrasound Transducer

A Doppler ultrasound transducer detects fetal heart movement for rate calculation. It is similar to the hand-held Doppler unit. The transducer sends high-frequency sound waves into the uterus. The sound waves are reflected, and the monitor's computer continuously calculates FHR based on the movement sensed as the heart beats. Fetal heart motion does not always correlate with electrical heart activity. Other movements, such as fetal or maternal activity or blood flow through the umbilical cord and the woman's aorta, also can be detected. Modern monitors ignore most of these extraneous sounds to provide a clean tracing. The Doppler transducer produces a two-part sound with each heartbeat. Fetal or maternal activity produces a rough, erratic sound rather than the crisp, rhythmic sound characteristic of fetal heart motion. Fetal hiccups cause a "th-thump" sound at regular intervals that is superimposed on sounds created by heart activity. Volume can be adjusted or turned off.

Uterine Activity Monitoring with a Tocotransducer

A tocotransducer ("toco") with a pressure-sensitive area detects changes in abdominal contour to measure uterine activity. The uterus pushes outward against the mother's anterior abdominal wall with each contraction. The monitor calculates changes in this signal and prints them as bell shapes on the lower grid of the strip. Movement other than uterine activity also registers on the monitor. For example, maternal respirations superimpose a zigzag appearance on the uterine activity line. Other fetal or maternal movements appear as spikes on the uterine activity tracing.

Expected outcome

After being taught about intrapartum fetal surveillance, the woman and her partner will express understanding of the equipment, procedures, limitations, and expected data.

BOX 17-1 POTENTIAL MATERNAL, FETAL, OR NEONATAL RISK FACTORS

Antepartum Period Maternal History • Prior stillbirth (unexplained or possibly recurrent cause) • Prior cesarean birth • Poor nutrition, low prepregnancy weight, poor weight gain • Multiple pregnancies, closely spaced • Chronic diseases, such as cardiac disease, anemia, hypertension, diabetes, asthma, and autoimmune diseases • Acute infections, such as urinary tract, pneumonia, gastrointestinal • Hematologic problems, such as anemia, deep vein thrombosis • Drug use (includes prescription, over-the-counter, herbal preparations, illegal drugs) • Psychosocial stress, domestic violence Problems Identified during Pregnancy • Intrauterine growth restriction (IUGR) • Gestation >42 wk • Marked decrease in fetal movement • Multifetal gestation • Preeclampsia, eclampsia • Gestational diabetes • Placental abnormalities (placenta previa, abruptio placentae) • Maternal severe anemia • Maternal infection • Maternal trauma

Assessment of Fetal Oxygenation

Assess uterine activity for frequency, duration, and intensity of contractions and for uterine resting tone. Calculate MVUs for IUPC data if that is unit policy. Intervals for assessment and documentation are: •Active first stage labor: every 15 to 30 minutes shortly after a contraction •Second stage labor every 5 to 15 minutes Take the woman's temperature every 4 hours and then every 2 hours after the membranes rupture. Maternal fever increases the fetal temperature and fetal oxygen requirements. Assess the woman's pulse, respirations, and blood pressure at least hourly or with fetal assessments. Hypotension or hypertension may reduce maternal blood flow to the intervillous spaces. Vaginal examination (see Chapter 16) may be performed to evaluate specific FHR patterns—for example, to check for a prolapsed cord if a pattern of variable decelerations occurs.

Assessment for FHR

Assess what the woman or the couples bases knowledge

Uterine Activity Assessment

Assessment of uterine activity has four components: frequency, duration, and intensity of the contractions; and uterine resting tone. Palpation is used to estimate contraction intensity and uterine resting tone when an external uterine activity monitor is used (see Procedure: External Fetal Monitor). Contraction frequency and duration are measured with EFM as with palpation (beginning of one contraction to beginning of the next). Contraction intensity is described as mild, moderate, or strong. The uterus should relax between contractions for at least 30 seconds. With the IUPC, the scale on the strip is used to describe intensity and resting tone. Contraction intensity changes as labor progresses. Average resting tone is 5 to 15 mm Hg. Contraction intensity with the IUPC is about 50 to 75 mm Hg during labor, although it may reach 110 mm Hg with pushing during second stage. Montevideo units (MVUs) may be used to describe contraction intensity in millimeters of mercury when an IUPC is used. The MVU is calculated by noting the contraction intensity in millimeters of mercury above the resting tone and multiplying by the number of contractions in 10 minutes. For example, if a woman has three contractions in 10 minutes, each of which has an intensity of 110 mm Hg and a resting tone of 15 mm Hg, the result in MVUs is 285. Excess uterine activity during labor would be 400 MVUs (Harmon, 2009).

Reassuring (Normal) Assessments

Baseline FHR: Stable, rate 110-160 bpm Moderate variability (6-25 bpm) Accelerations: Peaking at least 15 bpm above the baseline with a duration of 15 sec or more (10 bpm and 10 sec if gestation 32 weeks or less) Variable decelerations of less than 60 sec with rapid return to baseline, accompanied by normal baseline rate and moderate variability Uterine Activity: Contraction frequency: No more frequent than every 1½ min (or 5 within 10 min) Contraction duration: No longer than 90-120 sec Interval between contractions: At least 30 sec Uterine resting tone: Uterus relaxed between contractions (by palpation when intermittent auscultation or external fetal monitoring is used); uterine resting tone <20 mm Hg (with IUPC) Montevideo units: <400

SAFETY ALERT: Differences Between Early and Late Decelerations

Both Early and Late Decelerations • Decrease from the baseline fetal heart rate (FHR) and return to baseline are gradual (onset to nadir of at least 30 sec) • Occur with contractions • Rate decrease is rarely more than 30-40 beats per minute (bpm) below the baseline Early Decelerations • Are mirror images of the contraction (lowest point in FHR occurs with the peak of the contraction) • Return to the baseline FHR by the end of the contraction • Maternal position changes usually have no effect on pattern • Associated with fetal head compression • Are not associated with fetal compromise and require no added interventions Late Decelerations • Look similar to early decelerations but begin after the contraction begins (often near the peak). • Nadir occurs after the peak of the contraction. • Deceleration may remain in normal range and may not fall far from the baseline. • Reflect possible impaired placental exchange (uteroplacental insufficiency). • Occasional late decelerations accompanied by moderate variability, and accelerations are not ominous. • Persistent late decelerations, especially with no accelerations and absent or minimal variability, should be addressed by nursing interventions to improve placental blood flow and fetal oxygen supply.

Evaluating Auscultated Fetal Heart Rate Data

Both the fetoscope and Doppler transducer, a device that translates one physical quantity into another, can be used to identify FHR baseline, rhythm, and changes from the baseline (see Table 17-1, page 378). Because the fetoscope is detecting actual fetal heart sounds, it is reliable for detecting fetal dysrhythmias. The Doppler transducer (and external fetal monitor if it is being used for IA) also can be used to detect baseline, rhythm, and changes in the baseline. However, the Doppler transducer or external fetal monitor cannot be used to reliably detect fetal dysrhythmias. The fetoscope is rarely used in the United States despite its reliability in evaluation of fetal dysrhythmias.

PARENTS WANT TO KNOW: About Electronic Fetal Monitoring (Table)

Can I move around with the monitor? You can move freely with the monitor. If you notice that the machine isn't picking up the fetal heart sounds or contractions as well, call me and I'll readjust it. Make yourself comfortable; then we'll adjust the machine if necessary. What if I need to go to the bathroom? If you need to go to the bathroom, we'll unplug the cords from the machine and you can walk in there or we can roll the monitor to the door of the bathroom. There may be some circumstances in which walking or discontinuation of the monitor is not recommended. Will the monitor shock me? I don't know if I want to be hooked to an electrical outlet, especially since my water has broken Any monitor parts that are attached to you and your baby only transmit information into the machine for processing. The sensors on your body are isolated from electrical parts in the monitor. Why is the baby's heart beating so fast? A baby's heart normally beats faster than an adult's, both before and after birth. The normal rate is about 110 to 160 beats per minute. A higher or lower rate does not necessarily mean that the baby has a problem, but we do look at the monitor strip closely to see how the baby is doing. Why do those numbers for the baby's heart rate change all the time? The heart rate of a healthy baby who is awake changes constantly. When the baby moves, the heart often speeds up, just as yours does. If the baby sleeps, the heart rate may change less. What do those numbers for contractions on the machine (external monitor) mean? They change all the time The numbers reflect a change in the pressure that the monitor senses. The monitor senses many changes in pressure other than those from contractions, such as changes from breathing, coughing, or movement of you or the baby. My contractions don't look very strong, but they sure seem strong to me! (External uterine activity monitor is being used.) The external monitor senses contractions indirectly rather than sensing the actual pressure inside the uterus. Their appearance on the tracing varies because of many factors, such as your position, the position of the sensor on your abdomen, and the thickness of your abdominal wall. Will the internal monitor hurt my baby? The spiral electrode attaches only to the outer layer of skin on the baby's head. We avoid sensitive areas on the head, such as the fontanels (soft spots) or the face. The uterine catheter or fetal pulse oximeter slides up beside the baby.

Nonrassuring Patterns

Category III is used for nonreassuring patterns, or those in which favorable signs are absent or signs that are associated with fetal hypoxia or acidosis are present. Nonreassuring patterns do not necessarily indicate that fetal hypoxia or acidosis has occurred. They indicate that steps should be taken to identify possible causes for the patterns and correct their causes. Nonreassuring patterns include but are not limited to: •Absent baseline variability and •Recurrent late decelerations •Recurrent variable decelerations •Bradycardia •Sinusoidal pattern, a visually undulating pattern (rare)

Baroreceptors

Cells in the carotid arch and major arteries respond to stretching when the fetal blood pressure increases. These baroreceptors stimulate the vagus nerve to slow FHR and decrease the blood pressure, thus lowering cardiac output. As fetal blood pressure falls, the heart rate accelerates to maintain normal cardiac output.

Chemoreceptors

Cells that respond to changes in oxygen, carbon dioxide, and pH are chemoreceptors found in the medulla oblongata and in the aortic and carotid bodies. Decreased oxygen content, increased carbon dioxide content, or a lower pH in the blood or cerebrospinal fluid triggers an increase in the heart rate. However, prolonged hypoxia (low oxygen), hypercapnia (excess carbon dioxide in blood [elevated carbon dioxide partial pressure {Pco2}]), and acidosis (low pH from accumulation of acid [hydrogen ions] or depletion of base [bicarbonate ions]) depress FHR.

Placental Disruptions

Conditions such as abruptio placentae (separation of the placenta before birth) and infarcts (necrosis of varying amounts of placental tissue) reduce the placental surface area available for exchange. The amount and location of placental disruption relate to the degree of impairment in uteroplacental exchange.

Variable Deccelerations

Conditions that reduce flow through the umbilical cord result in variable decelerations. These decelerations do not have the uniform appearance of early and late decelerations. Their shape, duration, and degree of fall below baseline rate are variable. They fall and rise abruptly (within 30 seconds) with the onset and relief of cord compression, unlike the gradual fall and rise of early and late decelerations (Figure 17-11). Variable decelerations also may be nonperiodic, occurring at times unrelated to contractions.

uterine resting tone

Contraction intensity and the degree of uterine muscle tension, or uterine resting tone

Things to look for during uterine activity

Contractions that are too long (more than 90 to 120 seconds in duration) or too frequent (closer than every 2 minutes), a resting interval of less than 30 seconds, or a baseline (resting) intrauterine pressure of more than 20 mm Hg reduces the time available for normal uteroplacental exchange. Because of Glenda's diabetes and hypertension, uteroplacental exchange may be reduced before labor begins. Oxytocin stimulates uterine activity and can add to risk.

BOX 17-3 DOCUMENTING ELECTRONIC FETAL MONITORING

Documentation When Monitoring Is Initiated Monitor Strip Woman's name and hospital or other permanent identifying number Physician's or nurse-midwife's name Date and time of admission Date and time monitoring begins (verify accuracy of electronic monitor date and time) Gravidity, parity, abortions, living children Gestation in weeks Presence of identified risk factors Character of amniotic fluid (when membranes rupture) Function test of monitor accuracy Initial mode of monitoring (external or internal devices) Labor Record (If Paper-Only Documentation) Same information as on monitor strip First panel number when a printed paper strip begins Continuing Documentation Monitor Strip Maternal vital signs at appropriate intervals for stage of labor, membrane status, and interventions such as labor stimulation or pain management measures Notations of strip review at intervals appropriate for risk factors and labor status (see Box 17-2) Vaginal examinations, including cervical dilation and effacement and fetal station Rupture of membranes (spontaneously or artificially) Color, quantity, and character (such as foul odor, cloudiness) of amniotic fluid Maternal position changes Maternal or fetal movement that affects tracing Maternal vomiting, coughing, or other movement that affects tracing Summaries while pushing in second stage Equipment adjustments, problems maintaining continuous tracing (such as an active fetus) Medication and anesthesia, including related interventions Changes of equipment mode, such as external to internal device Interventions for nonreassuring patterns and maternal-fetal response Interruptions, such as the woman walking Labor Record Same information as on monitor strip Periodic summary of maternal vital signs, baseline rate, variability, periodic changes, and uterine activity (frequency, duration, and intensity of contractions and uterine resting tone) Nonreassuring maternal or fetal assessments, interventions, responses, provider notification, provider response Actions taken in chain of command if the physician or nurse-midwife does not respond appropriately to the nurse's report of a problem Note: Some of these actions may be entered automatically with electronic fetal monitoring (EFM) and computer interfaces.

uteroplacental exchange during labor

During labor, contractions gradually compress the spiral arteries, temporarily stopping maternal blood flow into the intervillous spaces. During contractions, the fetus depends on the oxygen supply already present in body cells, fetal erythrocytes, and the intervillous spaces. The oxygen supply in these areas is enough for about 1 to 2 minutes. As each contraction relaxes, freshly oxygenated maternal blood re-enters the intervillous spaces and waste-laden blood drains out.

EFM

EFM may be continuous, starting shortly after the woman is admitted, or intermittent, with a short recording made at regular intervals during labor, similar to auscultation. The most recent definitions are for visual interpretation of patterns, but the 2008 group recognized that computer programs for interpretation are being developed. Three categories, rather than the previous two categories, describe the fetus at that point in time and are not predictive of disorders such as cerebral palsy. Interventions may result in a change of the interpretation category

High tech or electronic fetal monitoring (EFM)

Electronic fetal monitoring (EFM) is the second approach to intrapartum fetal surveillance. Although EFM is dominant in U.S. hospital births, its routine use remains controversial because its benefits to the fetus are not always clear.

Enhancing comfort

Explain that staying in one position is uncomfortable and does not promote normal labor. The woman may assume any position other than supine unless a specific position is needed. Encourage her to find the position in which she is most comfortable; then adjust the external devices to best detect contractions and the fetal heartbeat. Internal devices may be an option if external devices cannot be adjusted to provide useful data. If the woman finds the sound produced by the electronic fetal monitor distracting or inconsistent with the atmosphere she desires, lower the sound or turn it off. Remember that the auditory cues for rate accelerations and decelerations are absent. If no other contraindications to walking exist, the woman may go to the bathroom when an electronic fetal monitor is used. Unplug the sensors at the machine and let her walk to the bathroom. Reconnect and adjust them when she returns. Alternatively, you may roll the machine to the door of the bathroom, keeping the cables connected. Sensors will need adjustment when she returns to bed, even if they were not disconnected. Document ambulation and other interruptions. If the fetus has a persistent nonreassuring pattern or internal sensors, it may be best not to interrupt the recording.

things to educate the parents on (interventions)

Explaining FHR Auscultation with Uterine Palpation, Explaining the Electronic Fetal Monitor, addressing safety concerns, and coping with misleading data, and including the labor partner, and enhancing comfort

Early Deccelerations

Fetal head compression for any reason increases intracranial pressure, causing the vagus nerve to slow the heart rate. Early decelerations are not associated with fetal compromise and require no intervention. They occur during contractions as the fetal head is pressed against the woman's pelvis or soft tissues, such as the cervix and are common during the second stage. Early decelerations are consistent in appearance; they are uniform in that one early deceleration looks similar to others. They mirror the contraction, gradually falling from the baseline and gradually returning to the baseline by the end of the contraction (Figure 17-9). The nadir (low point) of FHR occurs at the same time the contraction peaks. The rate at the nadir is usually no lower than 30 to 40 bpm from the baseline.

Fetal Monitoring Clocks

Fetal monitor clocks should be synchronized throughout the unit, often by connection to an atomic clock. Using the fetal monitor clock to determine the birth time allows the most accurate reconstruction of the events of labor. In legal proceedings, the amount of time required to accomplish corrective interventions can make a difference in the defense of a lawsuit.

Fetal alterations

Fetal tissues may be hypoxic despite an adequate oxygen supply from the mother and adequate exchange within the placenta. A low circulating fetal blood volume, fetal hypotension, or fetal anemia reduces the ability of fetal erythrocytes to deliver oxygen to body cells. Central nervous system or cardiac abnormalities may cause an abnormal rate or rhythm. For example, a fetus with complete heart block may not respond to stimuli that would normally cause a rate increase. Prolonged fetal bradycardia may be both a response to hypoxia and a contributing factor to hypoxia because fetal oxygenation is rate dependent. Prolonged tachycardia also can decrease cardiac output because the ventricles have less time to fill with oxygenated blood during diastole.

Fetal Heart Rate regulation

Five fetal factors that interact to regulate FHR include the: •Autonomic nervous system •Baroreceptors •Chemoreceptors •Adrenal glands •Central nervous system these mechanisms help to the cardiac output at a level to keep the fetal heart and brain oxygenated

Uterine Activity

Hypertonic contractions that are too long (≥90 to 120 seconds), too frequent (closer than every 2 minutes, or have an inadequate relaxation period (less than 30 seconds of complete relaxation) will not allow optimal uteroplacental exchange. Additional criteria may be specified when internal EFM is used. The uterus may never fully relax between contractions, applying continuous compression to the spiral arteries and reducing maternal-fetal exchange in the intervillous spaces. Excess uterine activity may occur with prostaglandin or oxytocin administration, but it may also occur with no external stimulation. A fetus with good oxygen reserve may never show signs of compromise, even with excessive contractions. Likewise, the fetus with little reserve may show compromise, even with weak uterine activity.

Reducing Cord Compression

If cord compression is suspected, the woman is repositioned. She may be turned from side to side, or her hips may be elevated to shift the fetal presenting part toward her diaphragm. Several position changes may be required before the pattern improves or resolves. The fetal presenting part may be pushed upward slightly. See also Chapter 27 for information about a prolapsed umbilical cord, an intrapartum emergency. Amnioinfusion, or infusion of sterile isotonic solution into the uterus, may be used to increase the fluid around the fetus and cushion the cord and reduce the likelihood of cesarean birth. Lactated Ringer's solution or normal saline is infused into the uterus through an IUPC. Amnioinfusion has been used to wash out or dilute fluid heavily stained with meconium, but research has been mixed on its effectiveness for this purpose

Evaluation of plan related to fetal oxygenation

If nonreassuring patterns are identified, the nurse: •Takes measures to increase fetal oxygenation. •Notifies the physician or nurse-midwife. •Documents all relevant data.

Late Deccelerations

Impaired exchange of oxygen and waste products in the placenta (uteroplacental insufficiency) may result in a pattern of late (delayed) decelerations. The fetus may develop acidemia, which can depress cardiac function, because poor oxygen availability in the placenta requires a shift to anaerobic metabolism. The cause of uteroplacental insufficiency may be acute and transient, such as maternal hypotension or excessive uterine stimulation. It also may occur with chronic conditions that impair placental exchange, such as maternal hypertension or diabetes. Although late decelerations are not reassuring, other signs can suggest whether the fetus is tolerating the uteroplacental insufficiency. A normal baseline rate with moderate variability and presence of accelerations suggests that the fetus is tolerating the conditions. However, the fetal reserves eventually will be depleted if the cause not corrected, and reassuring signs will disappear. Late decelerations look similar to early decelerations but are shifted to the right in relation to the contraction. They have a consistent and often subtle appearance in that one late deceleration looks similar to others. They gradually fall from the baseline and gradually return to the baseline after the contraction ends (Figure 17-10). The nadir of FHR occurs after the contraction

Increasing Maternal Blood Oxygen Saturatiion

Intervention: Administration of 100% oxygen at 8 to 10 L/min through a snug facemask makes more oxygen available for transfer to the fetus.

BOX 17-1 POTENTIAL MATERNAL, FETAL, OR NEONATAL RISK FACTORS (2)

Intrapartum Period Maternal Problems • Hypotension or hypertension • Hypertonic uterine contractions • Abnormal labor: preterm or dysfunctional • Prolonged rupture of membranes • Chorioamnionitis • Fever Fetal or Placental Problems • Fetal anemia • Persistent abnormal or nonreassuring fetal heart rate or pattern • Meconium-stained amniotic fluid • Abnormal presentation or position • Prolapsed cord • Abruptio placentae

Advantages of Auscultation and Palpation

Mobility is the primary advantage of auscultation and palpation for intrapartum fetal monitoring of the fetus at low risk. The woman is free to change position and walk, which is especially helpful during early labor or with a fetal occiput posterior position (see Chapter 16). She can use water-based methods of pain management, such as whirlpool baths or showers. The atmosphere is more natural than technologic, which is important to some families during their birth experience.

Variable Decelertions Sharp in onset and offset May occur as a periodic or nonperiodic (random) pattern

Nonreassuring if: Fall to less than 60 bpm for more than 60 sec Return to baseline prolonged Overshoots (exceeding baseline after deceleration) are present Accompanied by tachycardia and/or loss of variability Possible Causes: Umbilical cord compression, which may be secondary to: Prolapsed cord Nuchal cord (around fetal neck) Cord around fetal body parts Oligohydramnios (abnormally small amount of amniotic fluid) Cord between fetus and mother's uterus or pelvis, without obvious prolapse Knot in cord

Limitations of Auscultation and Palpation

One disadvantage of IA and palpation as the primary method of fetal assessment is that FHR and uterine activity are assessed for a small part of the total labor. Labor contractions place stress on the fetus because of the normal reduction of blood flow to the placenta at that time. Although FHR is assessed during some contractions, it is not recorded during every contraction. Continuous electronic or paper recording is not available on every Doppler to show the fetal response throughout labor or to identify subtle trends in the response. some women find the interruptions for auscultation distracting IA is staff intensive. Auscultation may not be a realistic option as the primary method of intrapartum fetal surveillance if the nurse-to-patient ratio must be greater than 1:1 for patients in normal labor.

Decreased or Absent Variability FHR baseline has a smooth, flat appearance

Possible Causes: Fetal sleep episodes (usually 40 min or less; occasionally as long as 2 hr) Fetal hypoxia with acidosis Drug effects: CNS depressants Local anesthetic agents

Tachycardia Baseline FHR >160 bpm for at least 10 min

Possible Causes: Maternal fever (fetal tachycardia may precede fever or other signs of infection) Maternal dehydration Maternal or fetal hypoxia Fetal acidosis Maternal or fetal hypovolemia Fetal cardiac dysrhythmias Maternal severe anemia Maternal hyperthyroidism Drugs administered to mother (such as terbutaline, bronchodilators, decongestants, stimulant drugs)

Bradycardia Baseline FHR <110 bpm for at least 10 min Baseline rates between 100 and 110 bpm are usually not associated with fetal compromise if there are no nonreassuring patterns

Possible Causes: Fetal head compression Fetal hypoxia Fetal acidosis Fetal heart block Umbilical cord compression Late second-stage labor with maternal pushing

PROCEDURE: External Fetal Monitor

Purposes To apply the electronic fetal monitor properly. To perform a basic evaluation of the fetal heart rate (FHR) and uterine activity patterns to identify data needing further assessment by the experienced nurse, physician, or nurse-midwife. 1. Review agency policy for use of the electronic fetal monitor and how it interfaces with computer documentation. 2. Verify that the date and time for the monitor are accurate and consistent with computer documentation. 3. Perform a function test, following the manufacturer's instructions, to ensure that the bedside monitor unit is calibrated properly to give accurate data. Each manufacturer sets standards for indicators of proper function. 4. To decrease the woman's fear of the unknown, explain the basic procedure of electronic fetal monitoring to the woman and her partner or family. Teaching her that she can move with the monitor in place enhances her comfort and promotes normal labor. Vary instructions according to equipment used and hospital protocols. A sample is: a.Using the electronic fetal monitor does not mean that you or the baby has a problem. It is a common way we assess the baby's response to labor contractions. b.Two belts go around your abdomen—one for the fetal heart rate sensor and one for contractions (three belts are needed for most twin pregnancies). c.Feel free to move with the monitor on. If the tracing is poor, we can adjust the sensors. 5. Apply belts, an adhesive ring, or other method to secure the sensors: a.Slide both belts under the woman's back without the sensors attached. To enhance comfort, keep the belts smooth under her back. b.An additional belt that is tied in a knot rather than attached to the ultrasound transducer may apply pressure against the sensor to better maintain ideal tilt against the maternal abdomen. A folded or rolled washcloth, roll of tape, or other simple techniques may be used similarly to maintain the best tracing. 6. Use Leopold's maneuvers (see Chapter 16) to locate the fetus's back because the fetal heart rate is best detected through the back of the fetus. 7. Apply ultrasound gel to the Doppler ultrasound transducer because gel improves transmission and reception of the ultrasound waves to provide more accurate data. Place the transducer on the woman's abdomen at the approximate location of the fetal back. Move the transducer until a clear signal is heard, tilting the sensor slightly (without losing contact) if needed for a clear signal. Most bedside units have a flashing heart-shaped light or other indicator of a good signal. Continuously changing numbers indicate the fluctuations of FHR. 8. Place the uterine activity sensor in the fundal area or the area where contractions feel the strongest when palpated because the external uterine activity monitor senses the change in the abdominal contour as the uterus rotates forward with each contraction. Contractions are usually strongest in the upper uterus. When the woman has a contraction, observe the tracing for the bell shape. The line for uterine activity is jagged because it also senses the rise and fall of the abdomen with breathing. Fetal or maternal movement causes a larger spike in the line. Observe through several contractions to verify correct placement, and improve placement if needed. 9. Observe the strip for baseline fetal heart rate, presence of variability, periodic changes, and uterine activity (contraction duration and frequency). Palpate contractions for intensity and relaxation between contractions to identify reassuring and nonreassuring fetal heart rate patterns (see Table 17-1). Contractions having a frequency greater than every 11/2 minutes (or 5 in 10 min), duration longer than 90 to 120 seconds, rest interval of less than 30 seconds, or incomplete uterine relaxation between contractions may reduce maternal blood flow into the intervillous spaces and impair exchange of oxygen and waste products. The external uterine activity sensor is useful for assessing contraction frequency and duration. It is not accurate for determining actual intensity or uterine resting tone. 10. Take corrective actions for nonreassuring patterns (p. 377). Notify the physician or nurse-midwife of nonreassuring patterns, corrective actions, and maternal and fetal responses. Document all calls, their content, and provider response.

Reassuring Patterns

Reassuring patterns, such as accelerations, often with fetal movement, are associated with fetal well-being. The nurse need only support optimal oxygenation because the patterns suggest that the fetus is tolerating intrapartum stressors.

Limitations of EFM

Reduced mobility is the major limitation of electronic fetal monitoring. Frequent maternal position changes or an active fetus may require constant adjustment of equipment to maintain a near-continuous trace. In addition, repositioning the equipment is necessary as the baby moves downward in the pelvis during labor. The belts or stockinette used to keep sensors positioned properly for external monitoring are uncomfortable for some women, and obtaining a good trace is often difficult for the woman with a thick abdominal fat pad. A woman may concentrate on maintaining a good tracing rather than making herself comfortable or using a position to enhance fetal rotation and descent. EFM and other procedures impart a technical air to the birth process and may be objectionable to a woman and her partner.

Fetal Scalp Stimulation

Scalp stimulation evaluates the fetus's response to tactile stimulation during labor (Figure 17-12). This procedure may be performed by a nurse, physician, or nurse-midwife. The examiner applies pressure to the scalp (or other presenting part) with a gloved finger or fingers and sweeps the fingers in a circular motion. An acceleration in FHR of 15 bpm for at least 15 seconds is a reassuring response in the term fetus, suggesting normal oxygen and acid-base balance. The acceleration may be delayed rather than immediate.

ANS

Sympathetic stimulation increases the heart rate and strengthens myocardial contractions through release of epinephrine and norepinephrine. The net result of sympathetic stimulation is an increase in cardiac output. The parasympathetic nervous system, through stimulation of the vagus nerve, reduces FHR and maintains variability. The parasympathetic branch gradually exerts greater influence as the fetus matures, beginning between 28 and 32 weeks of gestation. Which makes the heart rate in the term fetus lower than the pre term

Coping with misleading data

Teach the woman that the monitor data sometimes suggest a problem when none exists. For example, FHR may suddenly fall to zero and the audible tone stop if the sensor (external or scalp electrode) is displaced. Tell her to call the nurse for adjustment or replacement of the sensor. Explain that normal labor progress and fetal movement may alter the best location for assessing FHR externally by either auscultation or external EFM. The woman may be discouraged because the curves representing contractions on the electronic monitor do not look as strong on the strip as they feel to her. This situation is more likely if an external transducer is used. Explain the many factors that may cause the contraction curves to appear stronger or weaker than they really are. When an external tocotransducer is used, tell her that the strip is used mainly to assess the timing of contractions and the baby's reaction. Explain that an IUPC may be recommended if knowledge of intrauterine pressure is crucial. Explain also that data from the catheter may become inaccurate because of obstruction by amniotic fluid debris or pressure between the fetal head and pelvic structures during late labor. Reassure the woman that her perception of her contractions and discomfort is important. Value the woman-generated data as well as the machine-generated data. Palpate contractions at intervals and evaluate their appearance on the monitor strip. It is natural for the nurse's attention to be drawn to the electronic fetal monitor when entering the room. Stay focused on the woman and her family rather than devoting excessive attention to the monitoring equipment. The woman is having the baby, not the monitor.

Baseline Fetal Heart Rate

The FHR baseline is the average heart rate, rounded to 5 bpm, measured over 2 minutes of clear tracing within a 10-minute window. During this 2 or more minutes, the uterus must be at rest (Figure 17-6), and episodes of significant increases or decreases in rate must not occur. The baseline also excludes periodic and nonperiodic changes (see Figure 17-6, p. 373) or segments of the baseline that differ by more than 25 bpm.

Adrenal Glands

The adrenal medulla secretes epinephrine and norepinephrine in response to stress, causing a response from the sympathetic nervous system that accelerates FHR. The adrenal cortex responds to a decrease in the fetal blood pressure with release of aldosterone and retention of sodium and water, resulting in an increase in the circulating fetal blood volume.

Advantages of EFM

The electronic monitor supplies more data about the fetus than auscultation, and provides a permanent record that may be printed or stored electronically. Gradual trends in FHR and uterine activity are more apparent because the strip provides a graphic record for review. Continuous EFM shows the fetal response before, during, and after every contraction while it is in use rather than providing a sampling of fetal responses to contractions and between them. However the many studies of IA versus EFM have found the two techniques equally valid for the low-risk fetus (ACOG, 2009; Bashore & Koos, 2010; Harmon, 2009). EFM is prevalent in U.S. births that occur in hospitals. Most women entering the hospital for birth expect electronic monitoring, even if their pregnancy has been low risk. The woman and support person may find the constant sound of the fetal heartbeat comforting. The coach can use the tracing of contractions on the monitor strip to help the woman anticipate the beginning and end of each contraction. Electronic monitoring allows one nurse to observe two laboring women, primarily during uncomplicated early labor. A 1:1 nurse-to-patient ratio is needed during the second stage of labor or if high-risk conditions exist, regardless of the monitoring method used. Electronic monitoring gives the nurse more time for teaching and supporting the laboring woman with breathing and relaxation techniques if the nurse maintains the primary focus on the woman, not on the technology.

CNS

The fetal cerebral cortex causes the heart rate to increase during fetal movement and to decrease when the fetus sleeps. The hypothalamus coordinates the two branches of the autonomic nervous system. The medulla oblongata maintains the balance between stimuli that speed and stimuli that slow the heart rate.

Fetal Circulation

The fetal heart circulates oxygenated blood from the placenta throughout the body and returns deoxygenated blood to the placenta. The umbilical vein carries oxygenated blood to the fetus, and the two umbilical arteries carry deoxygenated blood from the fetus to the placenta

Fetal Heart scalp electrode

The fetal scalp electrode (FSE) detects electrical signals from the fetal heart (Figure 17-4). Fetal or maternal movement interferes less with accuracy because the rate is calculated from electrical events in the fetal heart. The monitor unit generates a beeping sound with each fetal heartbeat, but the volume of the sound can be adjusted. Areas to avoid for electrode application are the fetal face, fontanels, and genitals. The wire from the electrode protrudes from the mother's vagina and is attached to a leg plate to provide electrical grounding. Because it barely penetrates the fetal skin (about 1 mm), the electrode is easily displaced. The tracing then becomes erratic or stops if the electrode is fully detached. Secure attachment of the electrode is often difficult if the fetus has thick hair. The electrode is removed by turning it counterclockwise about one and one half turns until it detaches.

Low tech

The low-tech approach uses intermittent auscultation (IA) of fetal heart rate (FHR) and palpation of uterine activity.

Evaluating Electronic Fetal Monitoring Strips

The nurse evaluates FHR tracing for baseline rate, variability, and any pattern of rate changes from the baseline. Uterine activity is evaluated by determining the frequency, duration, and intensity of contractions and by assessing uterine resting tone. FHR and uterine activity patterns must be evaluated together when assessing whether the fetal status is reassuring. Other data relevant to strip interpretation are maternal vital signs; maternal position; drug, anesthetic, or oxygen administration; character of the amniotic fluid; labor status; and procedures performed. If paper charting is used, these are recorded on a paper strip as well as in the paper labor record. Computer systems that link charting and electronic FHR tracings reduce duplicate entries.

Purpose of fetal surveillance

The purposes of antepartum and intrapartum fetal surveillance are to evaluate the fetal condition during pregnancy and to identify possible hypoxic insult to the fetus during labor. It can not detect a compromised fetus.

Interruptions in umbilical flow

The usual cause of interrupted blood flow through the umbilical cord is compression. Blood flow through the umbilical cord may be reduced by compression between the fetal presenting part and the pelvis, a nuchal cord (around the fetal neck), one that is wrapped around the fetal body, or a knot in the cord. It may occur with oligohydramnios, because the amount of amniotic fluid is inadequate to cushion the cord. The umbilical cord may become tangled around fetal body parts. The fetus may compress the cord by grasping with the hand. The thin-walled umbilical vein is compressed initially, reducing flow of more highly oxygenated blood into the fetus. This results in initial hypoxia with hypotension. Baroreceptors and chemoreceptors respond by accelerating FHR. Flow from the fetus to the placenta through the firmer-walled umbilical arteries falls as cord compression continues, resulting in hypertension from increased fetal blood volume. Baroreceptors respond to hypertension by stimulating the vagus nerve, thus reducing fetal blood pressure and slowing the fetal heart. The FHR again accelerates as pressure on the arteries, and then the vein, is relieved.

Increasing Placental Pefusion

The woman is positioned on her side to eliminate aortocaval compression, which reduces placental blood flow. Giving a bolus of isotonic intravenous fluid such as lactated Ringer's solution increases the maternal blood volume, which in turn improves perfusion of the placenta if hypotension develops secondary to regional block (see "Epidural Block," p. 396, in Chapter 18). Uterine activity reduces blood flow into the intervillous spaces, and a fetus with little reserve for stress may be unable to tolerate even normal contractions. Persistent excess uterine activity may compromise a fetus with normal reserves. If a woman is receiving oxytocin, it is discontinued so that uterine activity is not stimulated. A tocolytic drug, such as terbutaline (0.125 to 0.25 mg intravenously or 0.25 mg subcutaneously), may be given to reduce uterine activity.

Fetal Oxygen Saturation Monitoring

This method to identify the true need for operative intervention (cesarean or forceps birth) related to fetal hypoxia was the objective of this technique. No longer in use in the united states

Fetal Scalp Blood Sampling

This procedure is more complex than other intrapartum techniques and requires rupture of membranes. Normal scalp pH is 7.25 to 7.35. Acidosis is present if the pH is less than 7.20, and the clinician may hasten the birth by using forceps or cesarean delivery.

PROCEDURE: Auscultating the Fetal Heart Rate

To evaluate the fetal condition and tolerance of labor. 1. Explain the procedure to give information to the woman and her partner. Wash your hands with warm water to reduce the transmission of microorganisms and to make your hands warm when touching the woman's abdomen. 2. Use Leopold's maneuvers to identify the fetal back (see Chapter 16) because it usually is closest to the surface of the maternal abdomen, where fetal heart sounds are clearest. Illustrations show approximate locations of the fetal heart rate in different presentations and positions, whether assessing the fetus with auscultation or electronic fetal monitoring. 3. Assess the fetal heart rate (FHR) with a Doppler transducer or fetoscope. The external fetal monitor may be used for intermittent electronic fetal monitoring (short periods of electronic monitoring interspersed with periods with no fetal surveillance, such as maternal ambulation). 4. Doppler transducer (see Figure 17-1, B): Place water-soluble conducting gel over the transducer to make an interface for clear signal transmission, and turn it on. Place the transducer over the fetal back and move it until you hear clear sounds that represent the fetal heart motion. 5. Fetoscope (see Figure 17-1, A): Place the bell of the fetoscope over the fetal back. Part of the fetoscope, a head plate pressed against your forehead, may be attached to add bone conduction to the sound coming through the earpieces. Move the fetoscope until you locate where the sound is loudest. 6. With one hand, palpate the mother's radial pulse to verify that FHR is what is actually heard. If her pulse is synchronized with the sounds from the fetoscope or Doppler transducer, try another location for the fetal heart. Other sounds that may be represented by the Doppler are the funic souffle (blood flowing through the umbilical cord) or uterine souffle (blood flowing through the uterine vessels). The funic souffle is synchronized with the fetal heart and is the same rate; the uterine souffle is synchronized with the mother's pulse. 7. Count the baseline FHR for 30 to 60 seconds between contractions. Assessment during a contraction may clarify findings, but auscultation is difficult during contractions. Note accelerations or slowing of the rate. Other counting methods, such as counting for 6-second segments for a total of 1 minute, may be used. 8. Note reassuring signs that suggest the fetus is tolerating labor well: a.An average rate of 110 to 160 beats per minute (bpm) b.Regular rhythm c.Accelerations from the baseline rate d.No decrease in rate from the baseline rate 9. Note nonreassuring signs. An electronic fetal monitor is applied for continuous monitoring of FHR and more frequent assessments related to nonreassuring signs. Notify the physician or nurse-midwife for further evaluation if: a.Heart rate outside normal limits. Unexplained tachycardia or bradycardia for 10 minutes or longer b.Irregular rhythm c.Gradual or abrupt decrease in rate

Uterine Activity Monitoring with an Intrauterine Pressure Catheter

Two kinds of intrauterine pressure catheters (IUPCs) can be used to measure uterine activity, including contraction intensity and resting tone. These are: 1.A solid catheter with a pressure transducer in its tip (Figure 17-5). This catheter usually has an additional lumen for amnioinfusion, or infusion of sterile solution into the uterus (see p. 380). 2.A hollow, fluid-filled catheter that connects to a pressure transducer on the bedside monitor unit. Both types sense intrauterine pressure and increases in intraabdominal pressure, such as with coughing or vomiting. The solid catheter is not affected by height because its transducer is in the catheter. However, the sensor in its tip measures hydrostatic pressure from the amniotic fluid above the fetal presenting part as well as the pressure from uterine activity. Therefore, recorded intrauterine pressures from the solid catheter are higher than those from the fluid-filled catheter, and the nurse must consider this fact when assessing whether uterine activity is normal or hypertonic. Because it is simpler to use, the solid catheter is more often used than the fluid-filled catheter. The tip of the fluid-filled catheter in the uterus should be at the level of the transducer on the outside for best accuracy. If the tip is lower than the transducer, the recorded pressure is lower than the actual intrauterine pressure. If the tip is higher, the recorded pressure may be artificially high. Changes in the mother's position may alter the height of the catheter tip, requiring adjustment of the transducer's height.

Cord Blood Gases and Ph

Umbilical cord blood analysis is used to assess the infant's acid-base balance immediately after birth rather than during labor. The samples are analyzed for pH, Pco2, oxygen partial pressure (Po2), and bicarbonate and for base deficit. This information helps identify whether acidosis exists and whether it is respiratory (short term), metabolic (prolonged), or mixed. Normal cord blood gases and pH can confirm that the fetus was adjusting normally to the stresses of labor, although the fetal monitoring pattern may have been nonreassuring or the 5-minute Apgar score low (see Table 16-3).

Late Deccelerations Gradual decelerations having a uniform appearance and a consistent relation to the contraction Onset to nadir of 30 sec or longer Nadir occurs after the peak of the contraction

Uteroplacental insufficiency, which may be secondary to: Maternal hypotension or hypertension Excess uterine activity, spontaneous or stimulated Placental interruption, such as abruptio placentae or placenta previa Maternal diabetes Maternal severe anemia Maternal cardiac disease

Variability

Variability describes the fluctuations in the baseline FHR that cause the printed line to have an irregular wavelike appearance rather than a smooth, flat one (Figure 17-7, p. 374). Previous use of short-term (beat-to-beat) variability and long-term (broad fluctuations in rate over 1 minute) variability is no longer standard

Evaluate and document the tracing and any nursing actions taken at the following times or according to facility policy:

a.Every 15 to 30 minutes during active first stage labor and every 5 to 15 minutes during second stage or as directed by facility policy and medical provider orders related to Glenda's high risk condition. b.Before and after procedures such as amniotomy (may result in cord compression), medications (may alter rate or variability of FHR), epidural anesthesia (possible hypotension that can reduce uteroplacental perfusion). c.With changes of activity, such as urination and repositioning, sensors may need adjustment. Changes of activity could alter the uterine or umbilical cord blood flow.

Indeterminate Patterns

are ones that do not fit into reassuring or nonreassuring category examples: •Tachycardia •Bradycardia with presence of variability •Minimal or marked baseline variability •Absent variability with no recurrent decelerations •Absence of accelerations after fetal stimulation •Periodic or episodic variations such as: •Recurrent variable decelerations accompanied by minimal or moderate baseline variability •Prolonged deceleration 2 minutes or longer but less than 10 minutes •Recurrent late decelerations with moderate baseline variability •Variable decelerations with other characteristics such as slow return to baseline and accelerations preceding or following ("overshoots," or "shoulders")

Accelerations

defined as atleast 15 bpm increase for atleast 15 seconds, generally considered a sign of a healthy fetus Accelerations lasting longer than 2 minutes but less than 10 minutes are prolonged accelerations. Accelerations that last 10 minutes or longer are a change in the baseline rate, or they may reflect a merging of several accelerations that later return to the previous baseline.

Nursing Care for a woman with intrapatrum fetal monitoring

heart auscultation or palpation and or EFM is acceptable for a woman with low risk factors, but is the preferred method for the woman that is high risk Two nursing care needs related to intrapartum fetal monitoring are the woman's (or couple's) learning needs and an expansion of nursing care related to fetal oxygenation. Care related to fetal monitoring by either electronic means or auscultation should be combined with that for normal or complicated intrapartum nursing as needed.

Two basic approaches are taken to intrapartum fetal surveillance

low tech or high tech each has limitations and advantages, neither is superior

Interventions related to fetal oxygenation

taking corrective actions if nonreassuring pattern is noted, reassuring parents, reporting nonreassuring patterns, and documenting assessments and care

Variability is a significant component of FHR tracing on the electronic monitor, for two reasons:

•Adequate oxygenation promotes normal function of the autonomic nervous system and helps the fetus adapt to the stress of labor. •Variability evaluates the function of the fetal autonomic nervous system, especially the parasympathetic branch.

Significance of FHR Patterns

•Category I: Normal (reassuring) •Category II: Indeterminate (often described as equivocal or ambiguous data) •Category III: Abnormal (nonreassuring)

Factors that affect apparent intensity as printed on the strip include:

•Fetal size. A small fetus does not allow the uterus to push firmly against the abdominal wall with each contraction, making contractions appear less intense. In addition, an immature fetus floats in a relatively larger quantity of amniotic fluid than a term fetus if membranes are intact. •Abdominal fat thickness. A thick layer of abdominal fat absorbs energy from uterine contractions, reducing their apparent intensity on the printed strip. Conversely, a thin woman whose uterus rotates sharply forward with each contraction may appear to have intense contractions when they are actually mild. Regular palpation of contractions should be done rather than relying only on the toco and contraction pattern. •Maternal position. Different maternal positions may increase or decrease pressure against the transducer. •Location of the transducer. Uterine activity is best detected where it is strongest and where the fetus lies close to the uterine wall. This location is usually over the upper uterus. Uterine contractions may not be detectable if the transducer is located elsewhere.

Variability may be decreased by several nonpathologic and pathologic factors, such as

•Fetal sleep •Narcotics or other sedative drugs, such as magnesium sulfate, given to the woman •Alcohol, illicit drugs •Fetal tachycardia •Gestation younger than 28 weeks •Fetal anomalies that affect central nervous system regulation of the heart rate, such as anencephaly •Hypoxia that is severe enough to affect the central nervous system •Abnormalities of the central nervous system, heart, or both •Maternal acidemia (low blood pH) or hypoxemia (reduced oxygen in blood)

Adequate fetal oxygenation requires five related factors:

•Normal maternal blood flow and volume to the placenta •Normal oxygen saturation in maternal blood •Adequate exchange of oxygen and carbon dioxide in the placenta •An open circulatory path between the placenta and the fetus through vessels in the umbilical cord •Normal fetal circulatory and oxygen-carrying functions

Ranges for Fetal heart rate

•Normal—A rate that averages from 110 to 160 bpm. The preterm fetus at 26 to 28 weeks often averages a rate at the upper end of this range because the parasympathetic nervous system, which slows the rate, is immature. Some healthy full-term fetuses have a rate that averages 100 to 110 bpm. •Bradycardia—Less than 110 bpm, persisting for at least 10 minutes. •Tachycardia—More than 160 bpm, persisting for at least 10 minutes.

Fetal Scalp Stimulation should be avoided if

•Preterm fetus (may cause or intensify contractions; may rupture intact membranes) •Prolonged rupture of membranes (higher risk of infection) •Chorioamnionitis (intrauterine infection) •Placenta previa (may cause hemorrhage) •Maternal fever of unknown origin (possibility of introducing microorganisms into the uterus)

Fetal Oxygenation and the nurses responsibility for planning

•Promote adequate fetal oxygenation. •Take corrective actions to increase fetal oxygenation if nonreassuring patterns are identified. •Report nonreassuring patterns to the physician or nurse-midwife. •Support the woman and her partner if a complication develops. •Document assessments and care.