In the USA, nearly 50% of all perinatal death occurs prior to birth. While fetal death from acute events such as cord accidents cannot be predicted, identifying, testing, and intervening for the fetus at risk for chronic in utero compromise may prevent neonatal and infant morbidity. This chapter discusses the antenatal assessment of fetal well-being.
An antepartum fetal test should reduce perinatal morbidity and mortality, and reassure parents. The test of choice depends on gestational age. When a fetus at risk for acidosis and asphyxia has reached viability, one of several tests may be employed for screening, including the nonstress test (NST), the contraction stress test (CST), fetal movement monitoring, the biophysical profile (BPP), and Doppler ultrasound. The specificity of these tests is generally high, while the sensitivity is highly variable. Diagnostic ultrasound and prenatal diagnostic procedures such as chorionic villus sampling (CVS) or amniocentesis are the most common tests performed during the early stages of pregnancy to identify chromosomal or major fetal anomalies.
The purpose of this chapter is to discuss common antepartum screening tests, including a description of each test, its indication, and its accuracy.
Perinatal mortality
Since 1965, the perinatal mortality rate (PMR) in the USA has fallen steadily, and the pattern of perinatal death has changed considerably. Improved techniques of antepartum fetal evaluation likely contribute to the decreasing PMR.