Pregnancy outcome after a primary antenatal hemorrhage between 16 and 24 weeks' gestation

Numerous studies have evaluated pregnancy outcome after previable antenatal hemorrhage, though nearly all of these have included first-trimester pregnancies. The study objective was to examine the pregnancy outcome after a primary antenatal hemorrhage that occurs between 16 and 24 weeks' gestation.

During a 12-year period, all pregnancies that experienced a first episode of antepartum hemorrhage occurring between 16 and 24 weeks' gestation were identified. Patients were excluded if they had any history of bleeding before 16 weeks' gestation, bleeding from a source other than the uterus, an examination consistent with incompetent cervix, or premature membrane rupture before the bleeding episode. All patients underwent an ultrasound evaluation and were separated into previa and nonprevia bleeding groups. Bleeding was categorized as heavy (equal or greater than a menstrual period or active bleeding seen at the initial examination) or light. Pregnancy loss was defined as a delivery before 24 weeks' gestation or neonatal death before hospital discharge. A preterm delivery was one that occurred between 24 and 37 weeks' gestation. A normal outcome was defined as a live infant free of major neonatal morbidity at the time of discharge.

During the study period, 128 patients met the criteria. Of these, 30 were classified as light (13 previa/17 nonprevia) and 98 were heavy (36 previa/62 nonprevia). In those with light bleeding, no statistical differences existed between previa and nonprevia bleeders and 26 (87%) had a normal outcome (95% confidence interval, 70-96%). In the 36 heavy bleeding previa cases, 6 (17%) pregnancies were lost and 24 (67%) had a normal outcome (95% confidence interval, 53-81%). In the 62 heavy nonprevia bleeding patients, 31 (50%) pregnancies were lost and a normal pregnancy outcome occurred in only 22 (35%) (95% confidence interval, 23-47%).

Overall pregnancy outcome after a primary light episode of antenatal hemorrhage between 16 and 24 weeks' gestation is fairly good. The prognosis is worse for heavy bleeding previa and nonprevia bleeding cases, but based on 95% confidence intervals, a normal outcome would be expected in greater than 50% of the placenta previa pregnancies vs a less than 50% expectation in nonprevia bleeding pregnancies.