Delivery of the growth-retarded infant.

Birth weight percentiles for gestational age were defined in 10,896 normal single live births of known maturity. Six hundred ninety-six infants with birth weights below the tenth percentile were compared with 574 controls to assess the effects of growth retardation and mode of delivery on fetal condition at birth. An Apgar score of less than 5 at 5 minutes was present in 112 growth-retarded infants and 50 normal infants; clinical fetal distress was present in 190 growth-retarded infants and 78 normal infants. Thirty growth-retarded infants died, 21 of them after 36 weeks' gestation. Apgar scores of less than 5 at 1 and 5 minutes were more often seen in immature infants, but the additional effect of growth retardation was not seen in this group. Forty-nine percent of the growth-retarded infants had low 5-minute Apgar scores after delivery by elective cesarean section, although less mature than the control group. Normal and breech deliveries were also more commonly associated with low scoring in growth-retarded infants, although immaturity was rare. Rotational forceps delivery was well tolerated. Breech and normal vertex deliveries were associated with depression at birth and increased perinatal mortality and morbidity in the growth-retarded infant, irrespective of maturity. Delivery by elective cesarean section was not shown to reverse this trend.