ch 6 antepartal tests

multiple marker screen timing

15-16 wks gestation

CVS timing

1st or 2nd trimester, ideally at 10-13 wks gestation

Delta OD 450 timing

2nd and 3rd trimester

fetal movement

3 or more discrete body or limb movements in 30 min are expected.

multiple marker screen advantages

60-80% of cases of Down syndrome can be identified. 85-90% of open NTDs are detected.

CVS risks

7% fetal loss rate due to bleeding, infection, and ROM. 10% expeience some bleeding after.

AFP advantages

80-85% of all open NTDs and open abdominal wall defects and 90% of anencephalies can be detected early in pregnancy.

amniocentesis risks

< 1% fetal loss rate after 15 wks gestation, increases 2%-5% earlier in gestation, trauma to fetus or placenta, bleeding, preterm labor, maternal infection, Rh sensitization from fetal blood into maternal circulation

polyhydramnios

AFI >24 cm. may indicate fetal malformations such as NTDs, obstruction of GI tract, fetal hydrops

maternal assays (alpha-fetoprotein/ a1-fetoprotein/maternal serum alpha-fetoprotein)

AFP is a glycoprotein produced in the fetal liver, GI tract, and yolk sac in early gestation. Assessing for levels of AFP in the maternal blood is a screening tool for certain developmental defects in the fetus such as fetal NTDs and ventral abdominal wall defects. because 95% of defects occur in the absence of risk factors, routine screening is recommended.

fetal activities that are last to develop

FHR variability, first to be diminished.

VAS interpretation

The NST using VAS is considered reactive when the FHR increases 15 beats above baseline for 15 sec twice in 20 min

tests of fetal status and well-being

daily fetal movement count (kick counts), non-stress test, vibroaccoustic stimulation, contraction stress test, amniotic fluid index, Biophysical profile

amniocentesis procedure

detailed ultrasound used to take fetal measurements to locate spot for needle insertion. a needle inserted transabdominally into uterine cavity using ultrasonography to guide placement. amniotic fluid is obtained. needs full bladder if less than 20 weeks.

Delta OD 450

diagnostic evaluation of amniotic fluid obtained via amniocentesis to predict life threatening anemia in the fetus during the 2nd and 3rd trimester. often done when alloimmunization exists, due to increased risk for severe fetal anemia from RBC hemolysis. UADF is a safer option in the management of Rh-alloimmunized pregnancies than Delta OD 450.

MRI

diagnostic radiological evaluation of tissues and organs from multiple planes. used to visualize maternal and fetal structures for detailed imaging when screening tests indicate possible abnormalities. most commonly performed for suspected brain abnormality.

fetal blood sampling/percutaneous umbilical blood sampling advantages

direct examination of fetal blood sample

daily fetal movement count advantages

done by pregnant women. inexpensive, easy, reassuring

MRI interpretation

done by radiologist

Delta OD 450 advantages

early evaluation and detection leads to early intervention, including fetal intrauterine transfusion, to increase chances of fetal survival

AFP nursing actions

educate on the test. assis in scheduling diagnostic testing when results are abnormal. provide info on support groups if NTD occurs

nursing actions for women undergoing antenatal testing

establish trusting relationship. assess for risk factors. explain how the test/procedure is performed. explain how the potential risks and benefits. explain what to expect during the test/procedure. explain what the test measures. encourage questions. encourage and foster open communication with providers. provide online resources. provide comfort. reassure the woman and her partner. provide psychological support. document the woman's response and the results of test.

amniocentesis advantages

examines fetal chromosomes for genetic disorders. direct examination of biochemical specimens

amniocentesis nursing actions

explain procedure and anesthetic will be used for the needle discomfort. full bladder may be needed if less than 20 weeks gestation. prep abdomen with antiseptic if indicated. assess fetal and maternal well-being after procedure monitoring and evaluating FHR. instruct to report abdominal pain, cramping, leaking of fluid, bleeding, decreased fetal movement, fever, chills. instruct to not lift anything heavy for 2 days. administer Rhogam to Rh- women post procedure as per order to prevent antibody formation in Rh- women.

UADF nursing actions

explain procedure, provide comfort. schedule appropriate follow-up.

4 indicators in BPP

fetal breathing movements fetal movement. fetal tone. amniotic fluid volume.

specialized ultrasound include those involving:

fetal doppler assessment, performance of biophysical profile, assessment of amniotic fluid, fetal echocardiography, or measurement of additional fetal structures

LBC of < or = 15,000/uL is highly indicative of

fetal lung immaturity

LBC of > or = 50,000/uL is highly indicative of

fetal lung maturity

positive PG indicates

fetal lung maturity

standard ultrasound used for evaluating:

fetal presentation, amniotic fluid volume, cardiac activity, placental position, gestational age, fetal number

determining gestational age by ultrasound through:

fetal-crown rump length, biparietal diameter, and femur length. most accurate before 20 wks

ultrasound advantages

gestational age, fetal growth, and detection of fetal and placental abnormalities. noninvasive. provides info on fetal structures and status

ultrasound used to obtain:

gestational age, fetal growth, fetal anatomy, placental abnormalities and location, fetal activity, amount of amniotic fluid, visual assistance for some invasive procedures such as amniocentesis

amniocentesis interpretations

has an accuracy of 99%. elevated bilirubin indicates fetal hemolytic disease. positive culture indicates infection. if the purpose is to detect fetal lung maturity, L/S ratio, phosphatidyl glycerol (PG), lamellar body count (LBC) are interpreted

VAS advantages

has reduced the incidence of nonreactive NSTs and reduced the time required to conduct NSTs.

CST nursing actions

have pt void before test. position in semifowlers. monitor vitals before and every 15 min during test. correctly interpret FHR and contractions. safely admin oxytocin. uterine tachysystole is more than 5 UCs in 10 min, fewer than 60 sec between contractions, or a contraction greater than 90 sec w/ a late deceleration occurring. recognize adverse effects of oxytocin.

NST nursing actions

have pt void prior to procedure and lie in semi-fowlers or lateral position. interpret FHR and accelerations and report to provider. document date/time, reason for test, maternal vital signs. typical interval for testing is biweekly or weekly depending on indication.

CST risks

high false positive rate, can result in unnecessary intervention. cannot be used w/women who have a contraindication for uterine activity.

AFP risks

high false-positive rate. can occur with LBW, oligohydramnios, multifetal gestation, decreased maternal weight, and underestimated fetal gestational age. false low levels can occur as a result of fetal death, increased maternal weight, and overestimated fetal gestational age.

modified BPP indicated for

high risk pregnancy related to maternal conditions or pregnancy-related conditions

fetal blood sampling/percutaneous umbilical blood sampling risks

high risk test. complications similar to amniocentesis and include cord vessel bleeding or hematomas, maternal-fetal hemorrhage, fetal bradycardia, and risk for infection. Fetal death rate is 1.4% but varies depending on induction.

negative PG indicates

immature fetal lungs

daily fetal movement count interpretation

in 2 hrs, 10 kicks is reassuring. once movement is achieved, counts can be stopped for the day. in 1 hr, 4 kicks is reassuring. should equal or exceed established baseline. report decreased movement. may need NST or BPP.

CVS procedure

in supine or lithotomy position depending on route of insertion. a catheter is inserted transvaginally or abdominally using ultrasound to guide it. small biopsy removed from placenta. villi is harvested and cultured for chromosomal analysis and DNA and enzymatic analysis

AFP interpretation of results

increased levels are associated with NTDs, anencephaly, omphalocele, gastrochisis. decreased levels are associated with trisomy 21 (down syndome). abnormal findings require additional testing such as amniocentesis, cvs, or ultrasonography to make a particular diagnosis.

L:S ratio < 2:1

indicates fetal lung immaturity in increased risk of resp distress syndrome

L:S ratio >2:1

indicates fetal lung maturity

daily fetal movement count nursing actions

instruct to lie on side while counting. if fetal movement is decreased, she should be instructed to have something to eat, rest, and focus on fetal movement for 1 hr.

VAS nursing actions

interpret FHR and accelerations and conduct VAS. report results and schedule followup

MRI nursing actions

involved in pre and post procedure. explain procedure.

AFI advantages

is a reflection of placental function and perfusion to the fetus as well as overall fetal condition.

daily fetal movement count

kick counts to identify hypoxic fetuses.

modified BPP advantages

less time to complete. predictive of fetal well-being.

transvaginal ultrasound

lithotomy position, done in 1st trimester

multiple marker screen interpretation

low levels of MSAFP and unconjugated 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.

BPP advantages

lower false positive rate

multiple marker screen procedure

maternal blood is drawn and sent out to lab.

AFP procedure

maternal blood is drawn and sent to lab for analysis.

LBC results can be hindered by

meconium, vaginal bleeding, vaginal mucous, or hydramnios

Delta OD 450 risks

membrane rupture, infection, worsening sensitization, fetal loss

CST procedure

monitor FHR and fetal activity for 20 min. if no spontaneous UCs, contractions can be triggered by brushing the nipple for 10 min. if nipple stimulation unsuccessful, admin oxytocin via IV until 3 UCs in 10-20 min lasting 40 sec occur.

3-dimensional and 4-dimensional ultrasound

more advanced types of ultrasound that takes thousands of images at once to produce a 3d or 4d image. allows for visualization of complex facial movements and features, branching of placental stem vessels, and connection of the umbilical vessels.

3D and 4D advantages

more detailed assessment of fetal structures, 3D presentation of placental blood flow, measurement of fetal organs, 4D ultrasound allows for evaluation of brain morphology and identification of brain lesions

abdominal ultrasound

need a full bladder to elevate uterus out of pelvis during 1st half of pregnancy. supine position.

fetal blood sampling/percutaneous umbilical blood sampling procedure

needle is inserted into the umbilical vein at or near placental origin and a small sample of fetal blood is aspirated. ultrasound used to guide needle.

CST advantages

negative CSTs are associated w/good fetal outcomes

VAS risks

no adverse effects reported, not recommended as routine procedure in high risk pt

MRI risks

no known harmful effects

3D and 4D risks

none

AFI risks

none

BPP risks

none

UADF risks

none

daily fetal movement count risks

none

modified BPP risks

none

multiple marker screen risks

none

ultrasound risks

none

NST risks

none, high false-positive rate, 80-90% but low false-negative rate of less than 1%

umbilical artery Doppler flow

noninvasive screening technique that uses advanced ultrasound 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 ultrasound. commonly used with other diagnostic tests to assess fetal status in IUGR fetuses.

UADF advantages

noninvasive, allows for assessment of placental perfusion

NST advantages

noninvasive, easily performed, reliable indicator of fetal well-being

fetal blood sampling/percutaneous umbilical blood sampling nursing actions

nurses may be involved pre and post procedure. position client in a lateral or wedged position to avoid supine hypotension during fetal monitoring tests. have terbutaline ready in case uterine contractions occur during procedure. assess fetal well-being post procedure for 1-2 hrs via external fetal monitoring. educate on how to count fetal movements for when she goes home

3D and 4D ultrasound timing

ordered as needed for further evaluation of possible fetal anomalies such as face and cardiac and skeletal. commonly requested by patient.

BPP indicated in

pregnancies involving increased risk of fetal hypoxia, placental insufficiency such as maternal diabetes and hypertension

daily fetal movement count timing

primary method for all pregnancies after 28 wks. women may feel movement around 16-20 wks

MRI advantages

provides detailed images of fetal anatomy, useful for brain abnormalities and complex abnormalities of thorax, GI, GU systems

post-procedure interpretation is done by

radiologist, obstetrician, nurse midwife

goal of fetal testing

reduce the # of preventable stillbirths and avoid unnecessary interventions.

fetal blood sampling/percutaneous umbilical blood sampling

removal of fetal blood from the umbilical cord. the blood is used to test for metabolic and hematological disorders, fetal infection, and fetal karyotyping. can be used for fetal therapies such as RBC and platelet transfusions.

MRI procedure

remove all metallic objects, placed in supine position with left lateral tilt on the MRI table. abdominal area scanned.

fetal blood sampling/percutaneous umbilical blood sampling interpretation of results

results 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.

CVS interpretation

results available within a week. detailed info is provided on chromosomal abnormality detected.

CVS nursing actions

review procedure: this tests obtains amniotic fluid for genetic testing for fetal abnormalities. label specimens. auscultate fetal heart rate twice in 30 min. instruct the woman to report any abdominal pain or cramping, leaking of fluid, bleeding, fever, chills. administer Rhogam to Rh- women post procedure as per order to prevent antibody formation in Rh- women.

3D and 4D ultrasound procedure/results

same as abdominal ultrasound

Delta OD 450 nursing actions

same as amniocentesis

3D and 4D nursing actions

same as standard ultrasound

MRI purpose

scan tissue and organs

amniotic fluid index

screening tool that measures the volume of amniotic fluid with ultrasound to assess fetal well-being and placental perfusion. decreased blood flow to fetal kidneys results in reduction of amniotic fluid production and oligohydramnios. accurate in detecting fetal hypoxia.

NST

screening tool that uses EFM to assess fetal condition or well-being. The heart rate of a physiologically normal fetus w/adequate oxygenation and intact autonomic nervous system accelerates in response to movement. The NST records accelerations in the FHR in relation to fetal activity. most widely accepted and for high risk.

CST

screening tool to assess fetal well-being and uteroplacental function with EFM in women with nonreactive NST at term gest. purpose is to identify a fetus at risk for compromise thru observation of the fetal response to intermittent reduction in uteroplacental blood flow associated with stimulated uterine contractions.

normal findings for placenta

size, normal position and structure, and adequate amniotic fluid volume

AFI nursing actions

special training in OB ultrasound is required for evaluation of amniotic fluid volume.

BPP nursing actions

special training in OB ultrasound is required for interpretation of ultrasound components of the test. schedule follow up; can be 1 week or biweekly if specific pregnancy complications

modified BPP nursing actions

special training in ultrasound is required for interpretation of amniotic fluid volume. schedule follow up; can be 1 week or biweekly if specific pregnancy complications

3D and 4D ultrasound purposes

standard determination of gestational age, fetal size, presentation, and volume of amniotic fluid. determination of complications such as vaginal bleeding, ventriculomegaly, hydrocephaly, and congenital brain defects. diagnosis of fetal malformations, uterine or pelvic abnormalities, hypoxic ischemic brain injury, and inflammatory disorders of the brain

NST 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

NST interpretation

the NST is considered reactive when FHR increases 15 beats above baseline for 15 sec twice or more in 20 min. in fetuses less than 32 wks, 2 accelerations peaking at least 10 bpm above baseline and lasting 10 seconds in a 20 min period is reactive. presence of repetitive variable decelerations that are >30 seconds requires further assessment of amniotic fluid

umbilical artery Doppler flow interpretation of results

the directed blood flow within the umbilical arteries is calculated by the difference between the systolic and diastolic flow. As peripheral resistance increases, diastolic flow decreases and the systolic/diastolic increases. considered abnormal if systolic/diastolic ratio is above 95th percentile for gestational age, or a ratio above 3.0 or end diastolic flow is absent or reversed

ultrasonography

the use of high frequency sound waves to produce an image of an organ or tissue. most common diagnostic test during pregnancy

nurses must understand:

the variety of tests available during pregnancy, the risks and benefits of tests/procedures, indications for the test/procedure, interpretation of findings

purpose of antenatal testing

to validate fetal well-being or identify fetal hypoxemia and to intervene before permanent injury or death occurs.

fetal activities that appear earliest in pregnancy

tone and movement, last to cease.

multiple marker screen

triple marker screening: combines all 3 chemical markers- AFP, hCG, estriol levels- with maternal age to detect some trisomies and NTDs. sometimes used as an alternative to amniocentesis. Quad screen: adds inhibin-A to the triple marker screen to increase detection of trisomy 21 to 80%

BPP

ultrasound assessment of fetal status along with NST. involves evaluation of fetal status through ultrasound observation of various fetal reflex activities that are CNS controlled and sensitive to fetal hypoxia. If fetal oxygen consumption is reduced, there is reduction of activity regulated by the CNS. provides prognostic info; evaluates parameters associated with chronic and acute.

AFI procedure

ultrasound measurements of pockets of amniotic fluid in 4 quadrants of the uterine activity

amniocentesis timing

usually 14-20 wks

fetal blood sampling/percutaneous umbilical blood sampling timing

usually used after ultrasound has detected an anomaly in fetus. may be done as early as 11 wks but is generally done in 2nd trimester to evaluate results of potential diagnoses and make further recommendations for medical management if necessary.

umbilical artery doppler flow procedure

woman is in supine position, transmission gel and transducer placed on abdomen, images are obtained of blood flow in umbilical artery

amniocentesis

a needle is inserted through the maternal abdominal wall into the uterine cavity to obtain amniotic fluid. commonly performed for genetic testing, assessment of fetal lung maturity, and assessment of hemolytic disease in fetus or for intrauterine infection.

amniotic fluid volume

a pocket of amniotic fluid that measures at least 2 cm in 2 planes perpendicular to each other is expected.

BPP interpretation

a score of 2 (present) or 0 (absent) is assigned to each of the 5 components. a total score of 8/10 is reassuring. score of 6/10 is equivocal and may indicate need for delivery depending on gestational age. score of 4/10 means delivery is recommended because a strong correlation with chronic apshyxia. score of 2/10 or less means immediate delivery. decreased fetal activity occurs in reverse to normal development.

vibroacoustic stimulation

a screening tool that uses auditory stimulation (using artificial larynx) to assess fetal well-being with EFM when NST is nonreactive. May be effective in eliciting a change in fetal behavior, fetal startle movemrnts, and increased FHR variability. Only used when the baseline rate is determined to be within normal limits.

normal findings for the fetus

age, size, viability, position, and functional capacities

Delta OD 450 procedure

amniotic fluid is collected via amniocentesis and used in a lab to determine whether there is a deviation of optical density (OD) at 45 nm.

limited ultrasound can be used to measure:

amniotic fluid volume, to evaluate interval growth, evaluate the cervix, to confirm fetal cardiac activity or fetal presentation

chorionic villi sampling

aspiration of a small amount of placental tissue for chromosomal, metabolic or DNA testing. used between 10-12 wks. detects fetal abnormalities caused by genetic disorders. tests for metabolic disorders such as cystic fibrosis but not neural tube defects

ultrasound nursing actions

assess for latex allergies if transvaginal. sterile sheathed probe is inserted for transvaginal ultrasound. not painful but may feel pressure. document ultrasound exam.

umbilical artery Doppler flow purposes

assess placental perfusion, assess fetal status in IUGR fetuses used in combination with other diagnostic tests, not useful for determining fetal compromise, not recommended for general OB population

BPP assessment includes

assessment of fetal breathing movement, gross body movement, fetal tone, amniotic fluid volume, heart rate reactivity

nurse's role in antepartal testing

assessment of risk factors, providing information and emotional support and comfort to women undergoing antenatal tests

multiple marker screen nursing actions

assist in scheduling additional testing if needed.

AFI interpretations

average measurement: 8-24 cm. abnormal AFI is <5 cm: oligohydramnios (prenatal mortality). decreased uteroplacental perfusion> decreased renal blood flow>decreased urine>oligohydramnios

biochemical assessment

biological exam and chemical determination. procedures are chorionic villi sampling, amniocentesis, maternal assays

biophysical assessment

can assess fetal movement, urine production, observe fetal structures and blood flow. tests used for biophysical assessment include ultrasonography, umbilical artery doppler flow, MRI

CVS advantages

can be performed earlier than amniocentesis but not recommended before 10 wks, examination of fetal chromosomes

modified BPP

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

modified BPP procedure

combines the use of an NST with an AFI

VAS procedure

conducted by activating an artificial larynx on the maternal abdomen near the fetal head for 1 sec in conjunction with the NST. Can be repeated at 1 min intervals up to 3 times.

CST interpretation

considered negative or normal when there are no significant variable decelerations or no late decelerations in a 10 min strip with 3 UCs>40 sec assessed with moderate variability. CST positive where there are late decelerations of FHR with 50% of UCs usually assessed with minimal or absent variability. positive result been associated w/increased rate of fetal death, fetal growth restriction, lower 5 min apgar scores, cesarean section, and need for neonatal resuscitation due to neonatal depression. suspicious when intermittent late or variable decelerations; further testing may be done.

modified BPP interpretation

considered normal when the NST is reactive and the AFI is greater than 5 cm. an AFI <5 is indicative of oliohydramnios. oligohydramnios can be associated w/perinatal mortality, decreased amniotic fluid may be a reflection of acute or chronic fetal asphyxia.

BPP procedure

consists of an NST with the addition of 30 min of ultrasound observation for 4 indicators

fetal breathing movements

1 or more episodes of rhythmic breathing movements of 30 sec or movement within 30 min is expected

fetal tone

1 or more fetal extremity extension with return to fetal flexion or opening and closing of the hand is expected.