Fetal heart rate patterns and perinatal outcome of very-low-birthweight infants

The obstetric records of 125 infants weighing 500-1250 g who were born in 1978 and 1979 at the Helsinki University Central Hospital were studied retrospectively to find out any associations between fetal heart rate (FHR) patterns and perinatal outcome. FHR recordings of 79 fetuses were available for study. Normal reactive patterns were observed in nine, nonreactive in 54, decelerations in 58, silent patterns in 45 and combined distress patterns in 36 fetuses. The interval from the first pathological sign to delivery was up to 27 days. Five fetuses in the monitored group died in utero, 26 infants died neonatally and two later. The risk of neonatal death after pathological FHR patterns was lower than after an FHR pattern without abnormality. Idiopathic respiratory distress syndrome (RDS) was diagnosed in 32 infants, of whom 16 died. Forty-seven fetuses (59%) of the monitored group were delivered abdominally and 32 vaginally. The risk of RDS was not significantly associated with FHR patterns and mode of delivery. We conclude that unlike term fetuses, low-birthweight fetuses seem to benefit from a period of intrauterine stress reflected in abnormal FHR patterns, if caesarean section is used liberally.