Gestational vaginal bleeding and pregnancy outcome

The relation between vaginal bleeding and pregnancy outcome was examined in a prospective study of 3,531 women seeking prenatal care in New York City from 1975 through 1985. Women were interviewed in the second trimester or later and were followed up at delivery. The frequency of vaginal bleeding during pregnancy was 22%. Few maternal characteristics or exposures were predictive of bleeding, and those that were associated with an increased risk of bleeding were only marginally so. Risk factors included advanced maternal age, previous spontaneous or induced abortion, working during pregnancy, and certain gynecologic conditions (fibroids, cervical inflammation, and ovarian cysts). Severity of bleeding was examined in relation to birth weight and length of gestation at delivery. Light bleeding during pregnancy was not associated with decreased birth weight or with shortened gestation at delivery. Heavy bleeding was associated with a decrease in mean birth weight of about 100 g (p less than 0.05) but was not significantly associated with the risk of low birth weight (odds ratio (OR) = 1.7, 95% confidence interval (CI) 0.9-3.3). Heavy bleeding was associated with preterm delivery among private patients (OR = 6.4, 95% Cl 1.7-23.5) but not public patients (OR = 0.3, 95% Cl 0.1-1.4). First trimester bleeding of any severity was marginally associated with congenital malformations in the offspring (OR = 1.7, 95% Cl 1.0-2.9); the effect was the same for major and minor abnormalities. There was no association between first trimester bleeding and placental complications of pregnancy or the delivery of a stillborn infant.