Correlates of placental abruption.

All cases (884) of placental abruption reported on Washington State birth or fetal death certificates in 1980 and 1981 were compared with 789 randomly selected births from the same time period. The incidence of reported cases of placental abruption was 6.5 per 1000 total births. The combined stillbirth and first month death rate of all abruption cases was 21%. Increased risks of placental abruption were associated with pre-eclampsia, diabetes, and unmarried status. Neither parity nor maternal age was associated with an increased risk. Infants born after abruption were significantly smaller-for-gestation than control infants, more likely to be male, and had malformations more frequently than control infants. Apgar scores of liveborn abruption infants were significantly lower than those of controls after adjustment for infant weight, gestational age, and sex.