Antepartum Fetal Tests -Hypoxia / Asphyxia (Lack of Oxygen)
Antepartum tests are test performed to determine the condition of the fetus and intrauterine environment and can recognize hypoxia and/or asphyxia. These tests include but are not limited to a biophysical profile, a contraction stress test, Doppler ultrasound flow testing, fetal movement counting, a non-stress test, the oxytocin challenge test and ultrasound test.
Several conditions may be present to necessitate antepartum testing. Examples of such are, hypertensive disorders (preeclampsia), diabetes, decreased or low fetal movement, oligohydramnios (low amniotic fluid levels), slowed intrauterine growth, and pregnancies beyond term.
The Non-Stress Test (NST)
Generally, the non-stress test NST is the first test performed to determine the status of he fetus. It is based on the principle that when the fetus moves, its heartbeat usually increases. The NST evaluates fetal status by monitoring accelerations of the fetal heart rate in response to its own movements.
Biophysical Profile
The biophysical profile is an ultrasound that can supplement the NST. Here, the clinician checks, fetal tone and movement, breathing motions, and the amniotic fluid volume (indication of fetal stress) to assess the general health of the fetus. Then the four components of the test and the NST are given an individual score; 2 for normal (or present), 1 indicating decreased, and finally, 0 for abnormal. The maximum score is 10.
Contraction Stress Test (CST)
The CST is similar to the Non-Stress Test (NST), however, here the fetal heart Rate (FHR) is evaluated in terms of the response to contractions of the mother's uterus. Because it is more detailed and complicated then a NST, it is often used to confirm the results of an abnormal NST.
