| Test | Implications of Results | Risks |
|---|---|---|
| Nonstress Test (NST) | ||
| Requires electronic fetal monitoring | Reactive test—indicate intact central nervous system (CNS). | Noninvasive procedures |
| Correlates fetal movements with fetal heart rate (FHR) and intact fetal CNS; 90% of gross fetal movements associated with accelerations of the FHR | Nonreactive test—does not meet criteria for reactivity. May indicate fetal jeopardy. | No known contraindications |
| Breast Stimulation Stress Test (BSST) | ||
| Can be performed by stimulation of nipples until contraction occurs | Contractions can be stimulated | May be contraindicated in preterm gestation |
| Contraction Stress Test (CST) | ||
| Correlates fetal heart rate response to induced uterine contractions; indicator of uteroplacental insufficiency | Increased doses of oxytocin are administered to stimulate uterine contractions. Interpretation:
| Invasive procedure Risk for uterine hyperstimulation and jeopardy to the fetus |
| Ultrasound | ||
| Passage of high-frequency sound waves through uterus to obtain data regarding fetal growth, placental position, placental detachment, and uterine cavity; can be done abdominally or vaginally | May be used for: pregnancy confirmation, fetal viability, estimation of fetal age, placental location, placental abruption, detection of fetal abnormalities, identification of multiple gestation, and confirmation of fetal death. | Noninvasive procedure Inconclusive evidence of harmful effects on humans |
| Biophysical Profile (BPP) | ||
| Assessment of five fetal biophysical variables: tone, breathing movements, gross body movement, amniotic fluid volume (AFV), and FHR reactivity (monitored by nonstress test [NST]); first four variables assessed by ultrasound; score of 2 assigned to each normal finding, and 0 to each abnormal; maximum score: 10 | Used to: assess the fetus at risk for intrauterine compromise.
| Noninvasive procedure No known contraindications |
| Amniocentesis | ||
| Invasive procedure for amniotic fluid analysis; needle placed through abdominal wall to obtain designated amount of fluid for examination; ultrasound always precedes this procedure; possible after 14 weeks of gestation | Amniotic fluid (fetal cells) might be analyzed for chromosomal studies to detect: aberrations, inborn errors of metabolism; determine fetal lung maturity, presence of isoimmune disease, α-fetoprotein (AFP) levels for determination of neural tube defects, and presence of meconium. | Complications: <1%, but risks might include: onset of contractions; infections; placental, cord, fetal, or bladder puncture
|
| Percutaneous Umbilical Blood Sampling (PUBS; also called cordocentesis) | ||
Technique used to obtain pure fetal blood from the umbilical cord while the fetus is in utero; ultrasound done first to locate umbilical cord, then a needle is inserted through the maternal abdomen and into the fetal umbilical vein;  done in second and third trimesters; a paralytic agent, such as Pavulon, may be given to prevent fetal movement during the procedure | Indications for fetal blood sampling:
| Overall fetal loss risk <2%; complication rate after PUBS: <0.5% Complications include: failure to obtain sample, bleeding, premature rupture of membranes, chorioamnionitis, fetal bradycardia, Rh isoimmunization (women who are Rh-negative are given RhoGAM). |
| Chorionic Villus Sampling (CVS) | ||
| Involves obtaining a small sample of chorionic villi from edge of developing placenta between 10 and 12 weeks of gestation; can be accomplished either transcervically or transabdominally; use sterile procedure; chorionic tissue aspirated into a syringe | Because chorionic villi originate in zygote, they reflect the genetic makeup of the fetus. Indications for CVS:
| Vaginal bleeding, spontaneous abortion (SAB), rupture of membranes, limb anomalies (increased risk if done <10 weeks of gestation); intrauterine infection, Rh isoimmunization (women who are Rh-negative are given RhoGAM) |