The relationship between assessed obstetric risk and maternal-perinatal outcome.

The relationship between antepartum risk assessment and subsequent maternal and perinatal outcome was examined in a retrospective study of 430 randomly selected deliveries at the Oregon Health Sciences University during the 1986 calendar year. Antepartum risk scores at the initial prenatal visit and at 37 weeks' gestation were positively correlated with each other. Antepartum risk scores were correlated with maternal length of stay and maternal hospital charges, but not with gestational age, birth weight, or Apgar scores. Increased intrapartum risk scores were strongly correlated with increasing length of stay for mother and baby, lower birth weight, and lower estimated gestational age at birth. The ability of the risk-scoring system to predict selected adverse outcomes was then assessed using a high-risk cutoff score of 5 or greater. Sensitivity and positive predictive value were found to be quite low while specificity and negative predictive value were reasonably high. The results suggest that the risk-scoring system used at this institution is effective in identifying low obstetrical risk and that prenatal care reduces the probability of poor neonatal outcome among infants of women at high obstetrical risk identified through antepartum multivariate assessment. Two antepartum risk assessments, each measuring different factors, may be redundant. Not yet known are which specific factors by their identification result in more effective prenatal care.