Suboptimal pregnancy outcome among women with prior abortions and premature births.

Data from 25,958 consecutive UCLA deliveries were analyzed to determine the effect of prior abortions and premature births on current pregnancy outcome. Perinatal death rate, combining stillbirths and neonatal deaths, increased more than threefold among women with at least one prior premature in birth and at least one prior abortion and approached 18 per cent of current deliveries when there were three or more prior premature births. Abnormal live births, defined as infants with either birth weight under 2,501 grams, gestational age less than 37 weeks, or congenital anomalies, significantly increased as the number of prior abortions and premature births increased, each in a range of 0 through 3 or more. For example, among women with at least three prior premature births, there were greater than 50 per cent abnormal live births. The risk was mostly that of low birth weight and low gestational age, although there was a slight increase in congenital anomalies. The risk was reduced considerably when there were previous term births and was influenced variably by race, clinic classification, maternal illness, and prior pregnancy complications. This empirical data on pregnancy outcome should be useful in reproductive counseling among women with pregnancy losses and premature births.