The beneits of antenatal fetal testing have not been suficiently evaluated in randomized controlled trials according to hacker and Berkelman (1986). This was concluded after reviewing 600 reports, which included only four randomized trials that were not powered to permit detection of important beneits. From their review, Enkin and colleagues (2000) concluded that "despite their widespread use, most tests of fetal well-being should be considered of experimental value only rather than validated clinical tools." nother important and unanswered question is whether antepartum fetal surveillance identiies fetal asphyxia early enough to prevent brain damage. Manning and coworkers (1998) studied the incidence of cerebral palsy in 26,290 high-risk pregnancies managed with serial biophysical proile testing. These outcomes were compared with those of 58,657 low-risk pregnancies in which antepartum testing was not performed. The rate of cerebral palsy was 1.3 per 1000 in tested pregnancies compared with 4.7 per 1000 in untested women. Todd and coworkers (1992) attempted to correlate cognitive development in infants up to age 2 years following either abnormal umbilical artery Doppler velocimetry or nons tress test results. Only abnormal nonstress tests were associated with marginally poorer cognitive outcomes. These investigators concluded that by the time fetal compromise is diagnosed with antenatal testing, fetal damage has already been sustained. Low and associates (2003) reached a similar conclusion.
According to the American College of Obstetricians and Gynecologists (2016), a normal antepartum fetal test result is , highly reassuring that a stillbirth will not occur within 1 week. This conclusion was reached after an analysis of reports of stillbirth rates associated with the various antepartum fetal heart rate tests (Table 17-4). Note that these results are corrected to remove lethal anomalies and unpredictable catastrophes such
TABLE 17-4. Stillbirth Rates within 1 Week of a Normal Antepartum Fetal Surveillance Test
Nonstress test 1s.9 5861 Contraction stress test OJ 12,656 Biophysical profile 0.8 44,828 Modified biophysical profile 0.8 54,61s7 aCorrected fot lethal anomalies and unpredictable causes of fetal death such as abruption or cord accident.
as placental abruption or cord accidents. The most important consideration in deciding when to begin antepartum testing is the prognosis for neonatal survival.
The severity of maternal disease is another. In general, with most high-risk pregnancies, testing begins by 32 to 34 weeks' gestation. P�egnancies with severe complications might require testing as early as 26 to 28 weeks. he frequency for repeating tests has been arbitrarily set at 7 days, but more frequent testing is often done.
Abramowicz JS, Sheiner E: Ultrasound of the placenta: a systemic approach.
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Alanne L, Hofren J, Haapsamo M, et al: Efect of sildenail citrate on fetal central hemodynamics and placental volume blood low during hypoxemia in a chronic sheep model. Abstract No. 25. Presented at the 37th Annual Meeting of the Society for Maternal-Fetal Medicine. January 23-28, 2017
American Academy of Pediatrics and American College of Obstetricians and Gynecologists: Guidelines for perinatal care, 8th ed. Elk Grove Village, AAP,o2017
American College of Obstetricians and Gynecologists: Antepartum fetal surveillance. Practice Bulletin No. 145, July 2014, Reairmed 2016