Antepartum testing in postterm pregnancy.

Antepartum testing in postdate pregnancy was reviewed. No method of testing has been uniformly found to prevent all antepartum deaths in pregnancies with confirmed dates greater than 42 weeks. Perinatal mortality varies according to both the test and the institution. When comparing results according to the method of testing, perinatal mortality appears to be lowest (1.8/1,000) with the use of a 3-cm vertical pocket on ultrasound. Nearly as good is the use of a contraction stress test (2.5/1,000) on a weekly basis. Ultrasound using a 1-cm pocket and a biweekly non-stress test (NST) resulted in slightly worse perinatal mortality (5/1,000 and 6/1,000, respectively). If variable decelerations during the NST are not interpreted as abnormal, the perinatal mortality using a biweekly NST is 15/1,000. Induction of labor at 41-42 weeks with a favorable Bishop score will obviate the need for antepartum testing in some patients.