PERINATAL OUTCOME WITH THE MODIFIED BIOPHYSICAL PROFILE

OBJECTIVE: Our purpose was to evaluate perinatal outcomes in high-risk pregnancies monitored with a modified biophysical profile. STUDY DESI GN: All non-insulin-dependent patients referred for antepartum fetal s urveillance received a modified biophysical profile biweekly. A modifi ed biophysical profile is a combination or a nonstress test and an amn iotic fluid index. Patients with a singleton gestation and intact memb ranes were entered into a protocol of randomized backup testing for an abnormal modified biophysical profile. Those patients having a nonrea ctive fetal heart rate, significant variable decelerations, late decel erations, or an amniotic fluid index less than or equal to 5.0 cm rece ived either a contraction stress test or a biophysical profile immedia tely. Once randomized, a patient received the same backup test, when i ndicated, with subsequent testing. RESULTS: A total of 2774 patients h ad 17,429 tests with an uncorrected perinatal mortality rate of 2.9 pe r 1000. The overall incidence of an adverse perinatal outcome (i.e., p erinatal death or nursery death before infant hospital discharge, cesa rean delivery for fetal distress within the first 2 hours of labor, Ei -minute Apgar score < 7, neonatal seizures or grade III or IV central nervous system hemorrhage) was 7.0%. When compared with patients havin g persistently normal modified biophysical profile, patients requiring a backup test had a significantly greater incidence of adverse perina tal outcome (9.3% vs 4.9%, p < 0.001, odds ratio 2.0, 95% confidence i nterval 1.5 to 2.7) and small-for-gestational-age infants (5.2% vs 2.4 %, p < 0.001, odds ratio 2.2, 95% confidence interval 1.5 to 3.5). No differences in outcomes between patients randomized to a contraction s tress test versus a biophysical profile could be identified either ove rall or in limiting the analysis to outcome after a negative last test . However, patients having contraction stress test as a backup test ha d a significantly higher rate of intervention for an abnormal test res ult than did those having a biophysical profile backup test (23.7% vs 16.6%, p < 0.002, odds ratio 1.6, 95% confidence interval 1.2 to 2.1). CONCLUSION: The modified biophysical profile is an excellent means of fetal surveillance and identifies a group of patients at increased ri sk for adverse perinatal outcome and small-for-gestational-age infants . There does not appear to be a significant benefit with the contracti on stress test compared with the biophysical profile as a backup test. Further, the contraction stress test is associated with a higher rate of intervention for an abnormal test than is the biophysical profile.