Labour & Fetal Monitoring

If the fetus suffers from oxygen deprivation, what signs might be present?

- fetal tachycardia - a pathological CTG and corresponding poor FBS result - fetal brachycardia or a severe change in fetal heart rate or decelerations related to uterine contractions, or both - passage of meconium-stained amniotic fluid

What is a CTG and what information does it provide?

A CTG or cardiotocograph, is the chart produced by the EFM and provides information on: - baseline fetal heart rate - baseline variability - accelerations from the baseline rate - decelerations from the baseline rate

What is considered to be preterm labour?

Before 37 weeks, regardless of birth weight.

How can the fetal condition be assessed during labour?

By obtaining information about the fetal movements, heart rate patterns, the pH of the fetal blood, and the colour and amount of amniotic fluid.

What is the main process occurring in the latent phase?

Cervical Effacement

What are the main processes occurring in the active and transitional phase?

Cervical dilation and descent.

Name some factors that might affect Power in labour.

Contractions affected by: - Hydration - Gravity/ maternal activity - Blood flow - Placentation - Infection - Medications

During labour, when is pulse measured?

Every 1-2 hours during early labour and every 30 min when labour is more advanced. If the rate increases to >100bpm, it may indicate anxiety, pain, infection, ketosis, or hemorrhage.

What are the seven cardinal movements?

Engagement-->or the entering of the biparietal diameter (measuring ear tip to ear tip across the top of the baby's head) into the pelvic inlet. Descent-->The baby's head moves deep into the pelvic cavity and is commonly called lightening. The baby's head becomes markedly molded when these distances are closely the same. When the occiput is at the level of the ischial spines, it can be assumed that the biparietal diameter is engaged and then descends into the pelvic inlet. Flexion-->This movement occurs during descent and is brought about by the resistance felt by the baby's head against the soft tissues of the pelvis. The resistance brings about a flexion in the baby's head so that the chin meets the chest. The smallest diameter of the baby's head (or suboccipitobregmatic plane) presents into the pelvis. Internal rotation-->As the head reaches the pelvic floor, it typically rotates to accommodate for the change in diameters of the pelvis. At the pelvic inlet, the diameter of the pelvis is widest from right to left. At the pelvic outlet, the diameter is widest from front to back. So the baby must move from a sideways position to one where the sagittal suture is in the anteroposterior diameter of the outlet (where the face of the baby is against the back of the laboring woman and the back of the baby's head is against the front of the pelvis). If anterior rotation does not occur, the occiput (or head) rotates to the occipitoposterior position. The occipitoposterior position is also called persistent occipitoposterior and is the common cause for true back labor. Extension-->After internal rotation is complete and the head passes through the pelvis at the nape of the neck, a rest occurs as the neck is under the pubic arch. Extension occurs as the head, face and chin are born. External rotation-->After the head of the baby is born, there is a slight pause in the action of labor. During this pause, the baby must rotate so that his/her face moves from face-down to facing either of the laboring woman's inner thighs. This movement, also called restitution, is necessary as the shoulders must fit around and under the pubic arch. It is at this point that shoulder dystocia may be identified. Shoulder dystocia occurs when the baby's shoulders are halted at the pelvic outlet due to inadequate space through which to pass. Mother's birthing babies who are identified as macrosomatic (in excess of 9.9 lbs.) are more likely to experience shoulder dystocia. Additionally, 15-30% of macrosomatic babies experiencing shoulder dystocia sustain some injury to the brachial plexus. Most of these injuries (80%) resolve by the baby's first birthday. Commonly, the McRobert's technique is used to resolve shoulder dystocia. This technique involves a sharp flexing of the maternal thighs against the maternal abdomen to reduce the angle between the sacrum and the spine. Expulsion-->Almost immediately after external rotation, the anterior shoulder moves out from under the pubic bone (or symphysis pubis). The perineum becomes distended by the posterior shoulder, which is then also born. The rest of the baby's body is then born, with an upward motion of the baby's body by the care provider.

Discuss Psychological state of the mother as it relates to labour.

Feeling of great intensity from excited anticipation to fearful expectancy. Anxiety can increase the production of adrenaline (epinephrine), which inhibits uterine activity and may in turn prolong labour. Mediated by: - Previous experience(s) - Support - Expectations / education / knowledge - Coping strategies / attitude - Relationship with baby - Fear / Anxiety vs Confidence / Trust - State of rest - Environment ....

Which stage of labour is the longest?

First stage.

Is it recommended that women have fetal monitoring?

It is recommended that women with uncomplicated pregnancies should not have EFM as a routine, but that intermittent auscultation with a Pinard stethoscope or handheld Doppler device should be the monitoring of choice. The fetal heart should be auscultated every 15min when the woman is in established labour.

During labour, when is respiratory rate measured?

It should be recorded at least every 4 hrs. It is a good indicator of the general physical condition of the woman. The rate may be over 20 respirations/min in severe anxiety or other pathologies.

Discuss Power as it relates to labour.

Labor must develop as a series of rhythmic contractions such that a net vector force is out. Irregular contractions and false labor (also called Braxton-Hicks contractions) may become strong enough to become very uncomfortable, but they don't effect enough of an organized force in one direction to push a baby downward and out against the cervix. In this way the baby's head cannot act as an effective dilating wedge to accomplish dilatation of the cervix, the criterion used to define the beginning of labor. On the other hand, the force of labor may no longer be enough at the end of long labors. The uterus may become fatigued.

Does the fetal heart rate change during contractions?

Normally the baseline rate is maintained during a contraction and immediately after it, however, in late labour some decels with contractions that recover quickly may be due to cord compression or compression of the fetal head and are normal. Variability of >5bpm should be maintained throughout labour.

What is the purpose of a partogram?

Partograms (or partographs) have become widely used as a means if recording the progress of labour. It is a chart on which the salient features of labour are entered in a graphic form and therefore provides the opportunity for early identification of deviations from normal. Most partographs consists of three sections: the maternal record, the fetal record, and the labour record. The charts are usually designed to allow for recordings at 15min intervals and include: - FHR - maternal temp - pulse - BP - details of vaginal examinations - strength of contractions - frequency of contractions in terms of the number in 10 min - fluid balance - urine analysis - drugs administered

What are the five P's affecting labour? (Sometimes referred to as the three P's)

Power Passenger Passageway Position of Mother Psychologic process of labour

What is tachycardia and brachycardia?

Tachycardia=a rate more rapid than 160bpm Brachycardia=a rate slower than 110bpm

What is the range of the baseline rate for the fetal heart rate?

Should be between 110 and 160 bpm.

During labour, when is temp measured?

Should be recorded at least every 4 hrs, and additionally when there is a clinical indication. This should remain within the normal range. Pyrexia is indicative of infection or ketosis, or may be associated with epidural analgesia.

Describe the fourth stage of labour.

The "fourth stage of labor" is a term used in two different senses: - It can refer to the immediate puerperium, or the hours immediately after delivery of the placenta. - It can be used in a more metaphorical sense to describe the weeks following delivery.

How should the fetal heart rate be measured?

The fetal heart should be counted over a complete minute in order to listen for the beat-to-beat variation. Variability can be confirmed by counting a number of fetal heartbeats heard in a 5s interval repeating this exercise for one minute.

Describe the first stage of labour.

The first stage of labour can be broken up into 3 phases: (1) The latent phase - may last 6-8hrs - form 0->3-4cm cervical dilation (in primis) - cervical canal shortens from 3cm to <0.5cm (2) The active phase - common to last 6-12hrs - cervix undergoes more rapid dilation (from 3-4cm to 10 cm) in the presence of rhythmic contractions (3) The transitional phase - when cervix is around 8cm until fully dilated (or until expulsive contractions)

What is the baseline fetal heart rate?

This is the fetal heart rate between uterine contractions.

Discuss Passageway.

When the Power is not an issue (adequate active labor) and the Passenger is not unduly large, the other factor to consider in a vaginal delivery is the birth canal. The birth canal is a layman's term usually meant to vaguely encompass the pelvis, cervix, and vagina. The pelvis, with it's hollowed out bony architecture, is the most important part. Soft tissue can elasticize to accommodate a baby, but bone will effectively stop a baby, causing head compression and possibly fetal distress. When the Power pushes the Passenger against a small Passageway, labor progress will stop.

When is labour considered to be 'normal'?

When: - The woman is near or at term - No complication exist - Single fetus presents by vertex - Labor is completed within 24 hours

What is the resting phase?

The lull in activity that sometimes occurs after full dilation but before the full expulsive nature of second stage contractions. Can be characterized by: maternal restlessness, discomfort, desire for pain relief, a sense that the process is never-ending and demands to attendants to get the birth over as quickly as possible.

Differentiate between 'false' and 'true' labour.

'False' labour, also known as Braxton-Hicks contractions, are frequent in late pregnancy and may or may not be painful. They can be distinguished from 'true' labour by the fact that they are irregular, often appearing sporadically and unpredictably, particularly at night.

What are some possible signs of second stage?

- Expulsive uterine contraction - Rupture of forewaters - Dilation and gaping of anus - A second show - Appearance of the presenting part

What are some of the signs that labour is starting?

- Lightening (baby drops) & relief of pressure at the fundus - Return of urinary frequency - Backache - Stronger Braxton Hicks contractions - Surge to energy ( and mood swings) - Increased vaginal discharge (Bloody show, mucus plug) - Cervical ripening - Rupture of membranes - GI upset (diarrhea, indigestion, nausea, vomiting)

During labour, when are abdominal examinations performed?

An initial abdominal examination is carried out when the midwife first examines the mother. This should be repeated at intervals throughout labour in order to assess the length, strength, and frequency of contractions and the descent of the presenting part.

How is amniotic fluid assessed?

Amniotic fluid escapes from the uterus continuously following rupture of the membranes. This fluid should normally remain clear. If the fetus becomes hypoxic, meconium may be passed as hypoxia causes relaxation of the anal sphincter-->amniotic fluid becomes green as a result of meconium staining.

What are some of the theories around what determines onset of labour?

Levels of maternal estrogen rise sharply during the last weeks of pregnancy, resulting in changes that overcome the inhibiting effects of progesterone. High levels of estrogen cause uterine muscle fibers to display oxtytocic receptors and form gap junctions with each other. Estrogen also stimulates the placenta to release prostaglandins that induce a production of enzymes that will digest collagen in the cervix, helping it to soften. Uterine activity may also result from mechanical stimulation of the uterus and cervix, brought about by overstretching or pressure from a presenting part applied to the cervix.

Discuss Position of the mother as it relates to labour.

Maternal position can affect her anatomic and physiologic adaptation to labor. -->Frequent changes of position during labor can help her relax, relieve fatigue, increase comfort, improve circulation and stay in control of the pain. Some positions: - Upright (walking, sitting, kneeling or squatting): i) Gravity assist in the descent of the fetus ii) Uterine contractions are stronger and more efficient shorter labor iii) Reduce the incidence of umbilical cord compression iv) Better maternal cardiac output improving blood flow to the placenta v) Reduce pressure on the maternal vessels and prevents their compression - All-four position or hands and knees position: i) Is used to relive backache, specially if the fetus is in an Occipitoposterior position.

During labour, when is BP measured?

Measured every 2-4 hrs unless it is abnormal, then more frequent recordings will be necessary. Hypotension may be caused by the supine position, shock or as a result of epidural anaesthesia.

Describe the second stage of labour.

The second stage is that of expulsion of the fetus. It begins when the cervix is fully dilated; in physiological labour the woman usually feels the urge to expel the fetus. It is complete when the baby is born. Typically lasts anywhere from 20 minutes to ~ 2hrs.

Discuss Passenger as it relates to labour.

The size and position of the baby are crucial factors in assuring a vaginal delivery. This means Lie, Presentation, Position, Attitude, Station, size of the fetal head and ability to mould.

Describe the third stage of labour.

The third stage is that of separation and expulsion of placenta and membranes; it also involves the control of bleeding. It lasts from the birth of the baby until the placenta and membranes have been expelled. Usually takes 3-5minutes, but can take up to an hour.

What are some of the factors that affect commencement of labour?

There is a great variability (influenced by parity, birth interval, presentation and position of the fetus, pelvic shape and size.

What are the indications for a vaginal examination in labour?

These are to: - make a positive identification of presentation - determine whether the head is engaged in case of doubt - ascertain whether the forewaters have ruptured, or to rupture them artificially (ARM) - exclude cord prolapse after rupture of the forewaters, especially if there is an ill-fitting presenting part or the fetal heart rate changes - assess progress or delay in labour - confirm full dilatation of the cervix - confirm the axis of the fetus and presentation of the second twin in multips, and if necessary in order to rupture the second amniotic sac