Chapter 6 Antepartal tests
2. Non-Stress Test (NST)(most common test)
- Screening tool that uses the electronic fetal monitoring (EFM) to assess fetal condition or well being. The HR of a physiologically normal fetus with adequate oxygenation and intact autonomic nervous system accelerates in response to movement. The NST records accelerations in the fetal heart rate (FHR) in relation to fetal activity. It is the most widely accepted method of evaluating fetal status, particularly for high risk pregnant women with complications such as hypertension, diabetes, multiple gestation, trauma, bleeding, woman's report of lack of fetal movement, and placental abnormalities. Procedure: The FHR is monitored with the external FHR transducer until reactive (up to 40 min) while running a FHR contraction strip for interpretation. Monitor FHR and fetal activity for 20-30 min. Interpretation: The NST is considered reactive when the FHR increases 15 beats above baseline for 15 seconds twice or more in 20 min. In fetuses < 32 weeks 2 accelerations peaking at least 10 bpm above baseline and lasting 10 seconds in a 20 min period is reactive. NONreactive NST is one w/o sufficient FHR accelerations in 40 min and should be followed up with further testing such as a BPP. Presence of repetitive variable decelerations that are >30 seconds requires further assessment of amniotic fluid. Advantages: noninvasive, easily performed, and reliable indicator of fetal well being. Risks: no indicated risks. NST has a high false-positive rate 80-90% but does have a low false-neg of < 1%. Nursing actions: Explain the procedure; The NST uses electronic fetal monitoring (EFM) to assess fetal well being. Have the pt void prior to the procedure and lie in a semi-fowlers or lateral position. Provide comfort measures. Provide emotional support. Interpret FHR and accelerations; report results to the care provider. Document the date and time the test was started, the pts name, and the reason for the test, and the maternal VS. Schedule appropriate follow up; the typical interval for testing is biweekly or weekly depending on indication.
Delta OD 450
-Diagnostic evaluation of amniotic fluid, obtained via amniocentesis to predict life threatening anemia in the fetus during the second and third trimester. The test often done when allimmunization exists, d/t the increase risk for severe fetal anemia from RBC hemolysis. Studies have determined that Umbilical Artery Doppler studies Flow is a safer option in the management of RH-alloimmunized pregnancies than Delta OD 450. Umbilical Artery Doppler flow is a non-invasive procedure which can measure the peak velocity of systolic blood flow in the middle cerebral artery of the fetus, and therefore does not involve the risk associated with amniocentesis. Timing: 2nd and 3rd trimester Procedure: Amniotic fluid is collected via amniocentesis and used in a lab to determine whether there is a deviation of optical density. Advantages: Early evaluation and detection leads to early interventions, including fetal intrauterine transfusion, to increase chances of fetal survival. Risks: membrane rupture, Infection, Worsening sensitization, Fetal loss. Nursing actions: see amniocentesis above.
Amniocentesis
-Diagnostic procedure in which a needle is inserted through the maternal abdominal wall into the uterine cavity to obtain amniotic fluid. It is commonly performed for genetic testing, assessment of fetal lung maturity, and assessment of hemolytic disease in fetus or for intrauterine infection. Risk factors for fetal genetic disorders include: advanced maternal age (>35 yrs), hx of genetic disorders, positive screening test such as a positive alphafetoprotein, and know or suspected hemolytic disease in the fetus. Timing: 14 - 20 weeks gestation Procedure: Detailed US is performed to take fetal measurements and located the placenta to choose a site for needle insertion. A needle is inserted transabdominally into the uterine cavity using ultrasonography to guide placement; Amniotic fluid is obtained. interpretation of results: Amniocentesis has an accuracy rate of 99%; Fluid sample is sent to lab for cell growth, and results of chromosomal studies are available within 2 wks. Elevated bilirubin levels indicate fetal hemolytic disease. A positive culture indicates infection. If the purpose of the test is to determine fetal lung maturity, lecithin/sphingomyelin (L/S) ratio, phosphatidyl glycerol (PG), lamellar body count (LBC), results are interpreted as follows: (done in 3rd trimester) L:S ratio >2:1 indicates fetal lung maturity L:S ratio <2:1 indicates fetal lung immaturity in increased risk of respiratory distress syndrome. Positive PG indicates fetal lung maturity; Negative PG indicates immature fetal lungs. A LBC of >50,000 is highly indicative of fetal lung maturity A LBV of <15,000 highly indicative of fetal lung immaturity. LBC results can be hindered by the presence of meconium, vaginal bleeding, vaginal mucous, or hydramnios. Advantages: Examines fetal chromosomes for genetic disorders; Direct examination of biochemical specimens. Risks: < 1% fetal loss rate after 15 weeks gestation; increases to 2%-5% earlier in gestation; Trauma to the fetus or placenta; Bleeding, preterm labor; Maternal infection; Rh sensitization from fetal blood into maternal circulation. Nursing Actions: Review the procedure with the pt and assure her that precautions are followed during the procedure with the US visualization of fetus to avoid fetal or placental injury. Explain that in the amniocentesis procedure a needle is inserted through the abdomen into the womb to obtain amniotic fluid for testing. Explain that during needle aspiration discomfort will be minimized with the use of a local anesthesia. Explain that a full bladder may be required for US visualization if the woman is < 20 weeks gestation. Instruct the woman in breathing and relaxation techniques she can use during the procedure. Provide comfort measures. Provide emotional support. Recognize anxiety r/t test results. Prep abdominal with an antiseptic such as betadine if indicated. Label specimens. Assess fetal and maternal well being post procedure, monitoring and evaluating the FHR. Instruct the pt to report abdominal pain or cramping, leaking of fluid, bleeding, decreased fetal movement, fever, or chills to the dr. Instruct woman not to lift anything heavy for 2 days. Administer Rho(D) immune globulin (RhoGAM) to Rh-negative women post procedure as per order to prevent antibody formation in the Rh-negative women.
Magnetic Resonance Imaging (MRI)
-Diagnostic radio logical evaluation of tissue and organs from multiple planes. During pregnancy, it is used to visualize maternal and/or fetal structures for detailed imaging when screening tests indicates possible abnormalities. It is the most commonly performed for suspected brain abnormality. Purpose: Scan tissue and organs. Procedure: The pt is instructed to remove all metallic objects b/f the test. Supine position with left lateral tilt on the MRI table; Abdominal area is scanned. Interpretation: Done by a radiologist. Advantages: provides very detailed images of fetal anatomy; particularly useful for brain abnormalities and complex abnormalities of thorax, GI and genitourinary systems. Risks: none Nursing Actions: Nurses are involved in the pre- and post procedure. Explain the procedure to the pt. The MRI is used to see maternal and/or fetal structures for detailed pictures. Address questions or concerns.
How are ultrasounds performed?
1. Trans vaginal Ultrasound: generally performed in the 1st trimester for earlier visualization on the fetus. lithotomy position; A sterile covered probe/transducer is inserted into the vagina. 2. Abdominal Ultrasound: A full bladder is necessary to elevate the uterus out of the pelvis for better visualization when abdominal ultrasound is performed during the 1st half of pregnancy. supine position; Transmission gel/transducer are placed on the belly. The transducer is moved over the belly to create an image of the structure being evaluated.
Advantages of having an Ultrasound:
Accurate assessments of gestational age, fetal growth, and detection of fetal and placental abnormalities; Noninvasive; Provides info on fetal structures and status.
Modified Biophysical profile
Combines an NST as an indicator of short term fetal well being and AFI as an indicator of long term placental function to evaluate fetal well being. It is indicated in high risk pregnancy r/t maternal conditions or pregnancy related conditions. Procedure: A modified BPP combines the use of an NST with an AFL. Interpretation: A modified BPP is considered normal when the NST is reactive and the AFI is greater than 5cm. An AFI less than or equal to 5 is indicative of oligohydramnios. Oligohydramnios is associated with increased perinatal mortality, and decreased amniotic fluid may be a reflection of acute of chronic fetal asphyxia. Advantages: Less time to complete; Predictive of fetal well being Risks: none Nursing Actions: Explain the procedure: A modified BPP is an NST and measurement of the amount of amniotic fluid. Provide comfort, Provide support;
Nursing actions for an Ultrasound:
Explain the procedure; Assess for latex allergies with trans-vaginal US and have pt put on gown and undress from waist down; For abdominal US, only lower abdomen needs to be exposed. Inform the pt that a sterile sheathed probe is used for trans-vaginal US and is inserted into the vagina. Inform her that she may feel pressure, but no pain is usually felt. Position pt in lithotomy for trans-vaginal US and supine for abdominal US. Provide comfort measures; Provide emotional support; Schedule appropriate follow-up; Document US exam.
Indications for US by Trimester of Pregnancy
First Trimester (last day of LMP - 14 weeks) - Confirm intrauterine pregnancy; Confirm fetal cardiac activity; Detect multiple gestation (number and size of gestational sacs); Assessment of amnionicity and chronionicity of multiples; Visualization during chorionic villus sampling; Estimate gestational age; Evaluate uterine structures; Detect missed abortion, tubal, or ectopic pregnancy. Second Trimester (15-28 weeks): Confirm the due date; Confirm fetal cardiac activity; Confirm fetal number, position, fetal size, amnionicity, and chronionicity; Confirm placental location; Confirm fetal weight and gestational age; Detect fetal anomalies (best after 18 weeks) or intrauterine growth restriction (IUGR); Visualize for amniocentesis; Evaluate uterine and cervical structures; evaluate vaginal bleeding; Third Trimester (29-40 weeks): Confirm gestational age; Confirm fetal viability; Detect placental abruption, previa, or maturity; Detect fetal position, congenital anomalies, IUGR; Assess biophysical profile (BPP); Assess amniotic fluid volume (AFI); Perform Doppler flow studies; Visualize for diagnostic tests and external version; Evaluate vaginal bleeding.
Psycho social factors
Maternal behaviors or lifestyles that have a negative effect on the mother or fetus. Ex: smoking, caffeine use, alcohol/drug use, and psychological status.
Biophysical factors
Originate from the mother or fetus and impact the development or function of the mother or fetus. They include genetic, nutritional, medical, and obstetric issues.
Interpretation of results of Ultrasound:
Post-procedure interpretation is typically done by a practitioner such as a radiologist, obstetrician, or nurse-midwife. After specialized training, nurses can perform limited obstetrical US. US for gestational age is determined through measurements of fetal-crown rump length, bi-parietal diameter and femur length. It is more accurate when performed b/f 20 weeks.
Timing of Ultrasounds
Standard ultrasounds are dones in the 1st trimester to confirm pregnancy and calculate gestational age.
Tests of Fetal Status and Well-Being:
This assessment of fetal status is a key component of perinatal care. A variety of methods are available for ongoing assessment of fetal well being during pregnancy. 1. Daily fetal movement count (kick counts) 2. Non-Stress test (NST) 3. Vibroacoustic stimulation (VAS) 4. Contraction stree test (CST) 5. Amniotic fluid index (AFI) 6. Biophysical profile (BPP) The goal of fetal testing is to reduce the # of preventable stillbirths and to avoid unnecessary interventions. The purpose of antenatal testing is to validate fetal well-being or identify fetal hypoxemia and to intervene b/f permanent injury or death occurs. Testing begins 32-34 weeks.
Multiple Marker Screen Triple marker screening and Quad Screen
Triple marker screening- Combines all three chemical markers AFP, HCG, and estriol levels with maternal age to detect some trisomies and NTDs. It is sometimes used as an alternative to amniocentesis. Quad Screen - adds inhibin-A to the trople marker screen to increase detection of trisomy 21 to 80%. Timing: 15-16 weeks gestation Procedure: Maternal blood is drawn and sent to the lab for analysis. Interpretation: Low levels of maternal serum alpha-feteoprotein (MSAFP) and unconjudated estriol levels suggest an abnormality. hCG and inhibin-A levels are twice as high in pregnancies with trisomy 21. Decreased estriol levels are an indicator of NTDs. Advantages: 60%-80% of cases of Downs syndrome can be identified and 85% - 90% of open NTDs are detected. Nursing Actions: Educate pt about the test. This is a maternal blood test that assesses for the levels of chemicals in the maternal blood to screen for certain developmental abnormalities. Provide emotional support for the woman and her family. Assist in scheduling additional testing if needed. Provide info on support groups if a NTD occurs.
Environmental factors
hazards in the workplace or the general environment that impact pregnancy outcomes.
Specialized Ultrasound
includes those involving fetal Doppler assessment, performance of biophysical profile (BPP), assessment of amniotic fluid, fetal echocardiography, or measurement of additional fetal structures.
Biochemical Assessment
involves biological examination and chemical determination. Procedures used to obtain biochemical specimens include: - Chorionic villi sampling, amniocentesis, percutaneous blood sampling, and maternal assays.
3D and 4D Ultrasound
more advanced types of trans-abdominal US that take thousands of images at once to produce a 3D or 4D image. They allow for visualization of complex facial movements and features, as well as the branching of placental stem vessels, and connection of the umbilical vessels to the chorionic plate of the placenta. Current recommendations are the 3D US be used only as an adjunct to conventional ultrasonography. Purpose: Standard determination of gestational age, fetal size, presentation, and volume of amniotic fluid. Determination of complications such as vaginal bleeding, ventriculomegaly, hydrocephyaly, and congenital brain defects. Diagnosis of fetal malformations, uterine or pelvic abnormalities, hypoxic ischemic brain injury, and inflammatory disorders of the brain. Timing: 3D and 4D US are ordered as needed for further evaluation of possible fetal anomalies such as face and cardiac and skeletal. 3D and 4D US are most commonly requested by the pt to see more life-like picture of their developing baby in-utero. Procedure (abdominal US) Advantages: More detailed assessment of fetal structures; 3D presentation of placental blood flow; Measurement of fetal organs; 4D US allows for evaluation of brain morphology and identification of brain lesions. Risks and nursing actions: same as standard US.
Biophysical assessment
ultrasonography, umbilical artery Doppler flow, and MRI
Ultrasonography
use of high frequency sound waves to produce an image of an organ or tissue. It is the most common diag test during pregnancy.
Standard Ultrasound
used for evaluating fetal presentation, amniotic fluid volume, cardiac activity, placental position, gestational age measurements, and fetal number. Other categories of US include limited obstetric US and specialized US, which usually are done after a standard US when deemed necessary for further fetal evaluation.
Sociodemographic factors
variables that pertain to the woman and her family and place the mothers and the fetus at increased risk. Ex: access to prenatal care, age, parity, marital status, income and ethnicity.
Biophysical Profile (BPP/BPA)
US assessment of fetal status along with an NST. It involves evaluation of fetal status through US observation of various fetal reflex activities that are CNS controlled and sensitive to fetal hypoxia. If fetal oxygen consumption is reduced, the immediate fetal response is reduction of activity regulated by the CNS. The BPP includes assessment of fetal breathing movement, gross body movement, fetal tone, amniotic fluid volume, and heart rate reactivity. The BPP provides improved prognostic infomation b/c physiological parameters associated in pregnancies involving increased risk for fetal hypoxia and placental insufficiency such as maternal diabetes and hypertension. Some controversy exists related to this tesst as a Cochrane Review concluded that available evidence from randomized clinical trials provides no support for the use of BPP as a test of fetal well being in high risk pregnancies . Procedure: BPP consists of an NST with the addition of 30 min of US observation for 4 indicators: fetal breathing movements, fetal movement, fetal tone, and measurement of amniotic fluid. Interpretations: A score of 2(present) or 0 (absent) is assigned to each of the five components. A total score of 8/10 is reassuring. A score of 6/10 is equivocal and may indicate the need for delivery depending on gestational age. A score of 4/10 means delivery is recommended b/c of a strong correlation with chronic asphyxia. A score of 2/10 or less prompts immediate delivery. Fetal activity decreases or stops to reduce energy and oxygen consumption as fetal hypoxemia worsens. Decreased activity occurs in reverse order of normal development. Fetal activities that appear earliest in pregnancy (tone and movement) are usually the last to cease, and activities that are the last to develop are usually the first to be diminished. Advantages: lower false-positive rate Risks: NONE Nursing actions: Explain the procedure: The BPP is an US evaluation of fetal status and involves observation of various fetal reflex activities with ultrasound and fetal monitoring. Provide comfort measures. Provide emotional support; Special training in obstetric US is required for interpretation of US components of the test. Schedule appropriate follow-up; The typical interval for testing is 1 week but for specific pregnancy complications may be bi weekly.
Limited Ultrasound
can be used to measure amniotic fluid volume, to evaluate interval growth, to evaluate the cervix, to confirm fetal cardiac activity or fetal presentation as an adjunct to US guided amniocentesis or external version, for confirmation of embryonic number, for measurement of crown-rump length, or for confirmation of a yolk sac or uterine sac with assisted reproductive technology.
Maternal Assays Alpha-Fetoprotein (AFP) Screening test
- glycoprotein produced in the fetal liver, GI tract, and yolk sac in early gestation. Assessing for the levels of AFP in the maternal blood is a screeing tool for certain developmentsal defects in the fetus such as fetal NTDs and ventral abdominal wall defects. Timing: 15-20 wks gestation Procedure: Maternal blood is drawn and sent to the lab for analysis. Interpretation of Results: Increased levels are associated with defects such as NTDs, anencephyaly, omphalocele, and gastroschisis. Decreased levels are associated with trisome 21 (downs syndrome). Abnormal findings require additional testing such as amniocentesis, chorionic villus sampling or ultraonography to make a particular diagnosis. Advantages: 80-85% of all open NTDs and open abdominal wall defects and 90% of anencephalics can be detected early in pregnancy. Risks: There is a high false positive rate (meaning the test results indicate an abnormality in a normal fetus) that can result in increased anxiety for woman and her family r/t identification of a potential defect as they wait for results of additional testing. High false positives can occur with low birth weight, oligohydramnios, multifetal gestation, decreased maternal weight, and underestimated fetal gestational age. False low levels can also occur as a result of fetal death, increased maternal weight, and overestimated fetal gestational age. Nursing actions: Educate the pt about the screening. The AFP test is a maternal blood test that evaluates the levels of AFP in the maternal blood to screen for certain fetal abnormalities. Support the woman and her family, particularly if results are abnormal. Assist in scheduling diagnostic testing when results are abnormal. Provide info on support groups if a NTD occurs.
Fetal Blood Sampling/Precutaneous Umbilical Blood Sampling (PUS) or cordocentesis
- the removal of fetal blood from the umbilical cord. The blood is used to test for metabolic and hematological disorders, fetal infection, and fetal karyotyping. It can also be used for fetal therapies such as red blood cell and platelet transfusions. Timing: Usually used after US has detected an anomaly in the fetus. may be done as early as 11 wks but is generally done in the second trimester evaluate results of potential diagnosis and make further recommendations for medical management if necessary. Procedure: A needle is inserted into the umbilical vein at or near placental origin and a small sample of fetal blood is aspirated. US is used to guide the needle. Interpretation of results: Results are usually available within 48 hrs. Interpretation of studies is based on the indication for the procedure. Biochemical testing on the blood may include a CBC with a differential analysis, anti-1 and anti-I cold agglutinin, B-HCG, factors IX and VIIIC, and AFP levels. Advantages: direct examination of fetal blood sample. Risks: Complications are similar to those for aminocentesis and include cord vessel bleeding or hematomas, maternal-fetal hemorrhage, fetal bradycardia, and risk for infection. The overall procedure related fetal death rate is 1.4% but varies depending on induction. Nursing actions: pre- and post procedures; Explain the procedure; During PUBS fetal blood is removed from the umbilical cord. Address questions and concerns. Position pt in a lateral or wedged position to avoid supine hypotension during fetal monitoring tests. Have terbutaline ready as ordered in case uterine contractions occur during procedure. Assess fetal well being post procedure for 1-2 hrs via external fetal monitoring. Educate pt on how to count fetal movements for when she goes home.
Umbilical Artery Doppler Flow
-A noninvasive screening tech that uses advanced US technology to assess resistance to blood flow in the placenta. It evaluates the rate and volume of blood flow through the placenta and umbilical cord vessels using US. This assessment is commonly used in combination with other diagnostic tests to assess fetal status in intrauterine growth restricted (IUGR) fetuses. Purpose: Assess placental perfusion; Used in combination with other diagnostic tests to assess fetal status in intrauterine growth restricted (IUGR) fetuses; Not a useful screening tool for determining fetal compromise and therefore is not recommended to the general obstetric population. Procedure: Supine; transmission gel/transducer are placed on woman's belly; Images are obtained of blood flow in the umbilical artery. Interpretation of results: The directed blood flow within the umbilical arteries is calculated using the difference between systolic and diastolic flow; As peripheral resistance increases, diastolic flow decreases and the systolic/diastolic increases. Reversed end-diastolic flow can be seen with severe cases of intrauterine growth restriction; Umbilical artery Doppler is considered abnormal if the systolic/diastolic (S/D) ratio is above the 95th percentile for gestational age, or a ratio above 3.0, or the end-diastolic flow is absent or reversed. Advantages: Noninvasive; Allows for assessment of placental perfusion; Risks: none Nursing Actions: Explain the procedure; The Doppler test evaluates the blood flow through the placenta and umbilical cord vessels using US. Address any questions, provide comfort, provide emotional support, and schedule appropriate follow-ups
Chorionic Villus Sampling CVS (faster results than amino)
-Aspiration of a small amount of placental tissue (chorion) for chromosomal, metabolic, or DNA testing. The test is used for chromosomal analysis between 10 and 12 weeks gestation to detect fetal abnormalities caused by genetic disorders. It tests for metabolic disorders such as cystic fibrosis but does not test for neural tube defects (NTDs). Timing: Performed during 1st or 2nd trimester ideally at 10-13 weeks. Procedure: Pt is supine or lithotomy depending on route of insertion; A catheter is inserted either transvaginally through the cervix using ultrasonography to guide placement or abdominally using a needle and ultrasongraphy to guide placement as well. A small biopsy of chorionic (placental) Tissue is removed. The villi are harvested and cultured for chromosomal analysis and processed for DNA and enzymatic analysis. Interpretation of results: Results of chromosomal studies are available within 1 week; Detailed info is provided on specific chromosomal abnormality detected. Advantages Can be performed earlier than amniocentesis, but is not recommended before 10 weeks; Examination of fetal chromosomes; Risks: There is a 7% fetal loss rate due to bleeding, infection, and rupture of membranes. 10% of women experience some bleeding after the procedure. Nursing Actions: Review the procedure with the woman and her family; This test obtains amniotic fluid to test for fetal abnormalities caused by genetic problems. Instruct the pt in breathing and relaxation techniques she can use during the procedure. Assist the pt into proper position (lithotomy for transvaginal aspiration; supine for transabdominal aspiration); Provide comfort measures; Provide emotional support; Recognize anxiety r/t results; Label specimens; Assess fetal rate and maternal well being post procedure. Fetal heart rate is auscultated twice in 30 minutes. Instruct the pt to report abdominal pain or cramping, leaking of fluid, bleeding, fever, or chills to the dr. Administer RhoGAM to Rh-negative women post procedure as per order to prevent antibody formation in Rh-negative women.
Common maternal conditions indicating needs for antenatal tests: Fetal Conditions
1. Intrauterine growth restriction 2. multiple gestation 3. Postterm pregnancy 4. Previous unexplained fetal demise 5. Ph isoimmunization 6. Fetal anomalies
Common maternal conditions indicating needs for antenatal tests: Pregnancy-related conditions
1. Pregnancy related hypertension 2. Decreased fetal movement 3. Hydramnios (condition that occurs when too much amniotic fluid builds up during pregnancy), Oligohydramnios (condition that occurs when there is not enough amniotic fluid), Polyhydramnios (too much amniotic fluid surrounding an unborn infant).
4. Contractions Stress Test (CST) (done in hospital if NST has no results)
-Screening tool to assess fetal well being and uteroplacental function with EFM in women with nonreactive NST as term gestation. The purpose of the CST is to identify a fetus that is at risk for compromise through observation of the fetal response to intermittent reduction in utero placental blood flow assoicated with stimulated uterine contractions. Procedure: Monitor FHR and fetal activity for 20 min. If no spontaneous UCs, contractions can be initiated in some women by having them brush the nipples for 10 minutes. If nipple stimulation is unsuccessful, UCs can be stimulationed with oxytocin via IV until 3 UCs in 10-20 min lasting 40 seconds occur. Interpretation: Positive test is BAD; The CST is considered neg or normal when there are no significant variable deceleration's or no late deceleration's in a 10 min strip with 3 UCs >40 seconds assessed with moderate variability. The CST is positive where there are late deceleration's of FHR with 50% of UCs usually assessed with minimal or absent variability. A positive result has been associated with an increased rate of fetal death, fetal growth restriction, lower 5 min Apgar scores, ceasarean section, and the need for neonatal resuscitation due to neonatal depression. This requires further testing such as BPP. The CST is equivocal or suspicious when there are intermittent late or variable deceleration's and further testing may be done or the test repeated in 24 hours. Advantages: Negative CSTs are associated with good fetal outcomes. Risks: CST has a high false positive rate which can result in unnecessary intervention. Cannot be used with women who have a contraindication for uterine activity. Nursing actions: Explain the procedure; The CST stimulates contractions to evaluate fetal reactions to the stress of contractions. have pt void before testing. position pt in semi-fowlers; Monitor vitals before and every 15 min during the test; provide comfort measures; Provide emotional support; Correctly interpret FHR and contractions. Safely administer oxytocin (avoid uterine tachsystole) Uterine tacysystole is defined as more than five uterine contraction sin 10 min, fewer than 60 seconds between contractions or a contraction >90 seconds with a late deceleration occurring. Recognize adverse effects of oxytocin. Schedule appropriate follow up.
Amniotic Fluid index (AFI)
-a screening tool that measures the volume of amniotic fluid with US to assess fetal well being and placental function. The amniotic fluid level is based on fetal urine production, which is the predominate source of amniotic fluid and is directly dependent on renal perfusion. In prolonged fetal hypoxemia, blood is shunted away from fetal kidneys to other vital organs. Persistent decreased blood flow to the fetal kidneys results in reduction of amniotic fluid production and oligohydramnios. In conjunction with NST, AFI is a strong indicator of fetal status, as it is accurate in detecting fetal hypoxia. Procedure: US measurement of pockets of amniotic fluid in 4 quadrants of the uterine cavity via US. Interpretation of Results Average measurement in pregnancy is 8-24cm . Abnormal AFI is below 5 cm. An AFI < 5cm is indicative of oligohydramnios. Oligohydramnios is associated with increased prenatal mortality and a need for clost maternal and fetal monitoring. Represented graphically: decreased uteroplacental perfusion: decreased fetal renal blood flow: decreased urine production: leads to oligohydramnios. An AFI above 24cm is polyhydramnios, which may indicate fetal malformation such as NTDs, obstruction of fetal GI or fetal hydrops. Advantages: AFI is a reflection of placental function and perfusion to the fetus as well as overall fetal condition. Risks: NONE Nursing Actions: Explain the procedure: This test measures the amount of amniotic fluid with US to assess fetal well being and how well the placenta is working. Provide comfort measures, Provide emotional support, schedule appropriate follow up, special training in obstetric US is required for evaluation of amniotic fluid volume.
1. Daily Fetal movement Count (kick count)
-maternal assessment of fetal movement by counting fetal movements in a period of time to identify potentially hypoxic fetuses. Timing: Kick counts have been proposed as a primary method of fetal surveillance for all pregnancies after 28 weeks gestation. Many women may begin feeling fetal movement around 16-20 weeks. Procedure: the pregnant woman is instructed to palpate her abdomen and track fetal movements daily for 1-2 hrs. Interpretation: In the 2 hr approach, maternal perception of 10 distinct fetal movements within 2 hrs is considered normal and reassuring once movement is achieved, counts can be d/c for the day. In 1 hr approach the count is considered reassurance if it equals or exceeds the established baseline: 4 movements in 1 hour. Reports of decreased fetal movement should be reported to dr and is an indication for further fetal assessment such as non stress test or biophysical profile. Fewer than 4 fetal movements in 2 hours should be reported to dr. Advantage: Done by pregnancy women. Inexpensive; Risks: NONE Nursing actions: Teach the pt how to do kick counts and provide a means to record them. Instruct the pt to lie on her side while counting movements. Explain that maternal assessment of fetal movement by counting fetal movements is an important evaluation of fetal well being. If fetal movement is decreased, the pt should be instrcted to have something to eat, rest, and focus on fetal movement for 1 hr. 4 movements in 1 hr is good. Instruct the pt to report decreased fetal movement to dr.
3. Vibroacoustic stimulation (VAS)
-screening tool that uses auditory stimulation (using an artificial larynx) to assess fetal well being with EFM when NST is nonreactive. Vibroacoustic stimulation may be effective in eliciting a change in fetal behavior, fetal startle movements, and increased FHR variability. VAS is only used when the baseline rate is determined to be within normal limits. When the deceleration or bradcardia is present, VAS is not appropriated intervention. Procedure: VAS is conducted by activating an artifical larynx on the maternal abdomen near the fetal head for 1 second in conjunciton with the NST. This can be repeated at 1 min intervals up to 3 times. Interpretation: The NST using VAS is considered reactive when the FHR increases 15 beats above baseline for 15 seconds twice in 20 min. Advantages: Using the VAS to stimulate the fetus has reduced the incidence of nonreactive NSTs and reduced the time required to conduct NSTs. Risks: No adverse effects reported. Not recommended as a routine procedure in high risk pregnancies. Nursing actions: Explain the procedure; the test uses a buzzer (in auditory stimulation) to assess fetal well-being. provide comfort measures; Provide emotional support; Interpret FHR and accelerations and conduct VAS appropriately. Report results to dr.
Nursing actions for Women undergoing Antenatal testing:
1. Establish a trusting relationship 2. one of the main functions of nursing is to promote informed decisions and prevent uninformed decisions by pts. 3. Assess for factors that place the woman and her fetus at risk for adverse outcomes. 4. Provide info regarding the test. 5. Provide comfort 6. Reassure the woman and her significant other 7. Provide psychological support to the woman and her significant other. 8. document the woman's response and the results of tests 9. Report results of tests to providers. 10. Reinforce info given by the woman's provider regarding the results of the tests and need for further testing, treatment, and referral.
Common maternal conditions indicating needs for antenatal tests: Preexisting Medical conditions
1. Hypertensive disorder 2. Renal disease 3. Pulmonary or cardiac disease 4. Autoimmune disease 5. Type 1 DM