Simultaneous antepartum testing of twin fetal heart rates

Assessment of twin gestation in the antepartum period has been a problem because most methods either fail to distinguish twins individually or require serial study over several weeks before reaching diagnostic end points. Electronic monitoring of the fetal heart rate (FHR) allows individual focus on each twin with a high degree of specificity and permits immediate status evaluation. In this study 44 sets of twins had simultaneous Doppler monitoring in an outpatient testing center. Transducer position was aided by real-time ultrasonic location of each fetal heart; 198 tests were satisfactory, each patient receiving 3.9 +/- 2.9 (mean +/- SD) studies. The rate of unsatisfactory tests was 15.4%, though each fetus was satisfactorily tested within one week of delivery. Testing was begun at 32.9 +/- 2.9 weeks and delivery occurred at 36.8 +/- 2.6 weeks. Perinatal mortality was 22.7/1,000, significant morbidity 15.9%, and cesarean section rate 18.1%. Reactive (R) patterns were seen in 69 fetuses and nonreactive (NR) in 19. Although there were no significant differences in gestational age at delivery between R and NR groups, (36.9 vs 36.2 wk) NR fetuses had significantly lower birth weights and higher rates of neonatal depression, perinatal mortality, and retarded intrauterine growth. Similarities in FHR patterns within twin pairs were frequently observed (30/44). Twins exhibiting dissimilar patterns had significant differences in birth weight and tended to have separate rather than common placentas. Simultaneous FHR testing of twins appears to be an effective means of providing immediately accessible data on the comparative well-being of each twin.