The outcome of pregnancies complicated by bleeding during the second trimester.

Vaginal bleeding during the second trimester has historically been associated with high perinatal mortality rates (33 to 82 per cent). Because this topic has not been specifically studied since the advent of obstetric ultrasound and electronic fetal heart rate monitoring, we reviewed the experience at the University of Utah with second trimester vaginal bleeding from 1 January 1983 through 15 June 1989. The cause of the bleeding was found to fit into four general categories. These are placenta previa, abruption, both previa and abruption, and other or unknown. Midtrimester bleeding is still associated with a high perinatal mortality rate (22.3 per cent), being highest when associated with placental abruption (36.6 per cent) and lowest with placenta previa (7.4 per cent). For the entire series, pregnancies maintained into the third trimester were associated with a much lower perinatal mortality rate than those in which delivery occurred during the second trimester (7.1 versus 54.5 per cent). These relatively improved outcomes suggest that aggressive obstetric management is warranted in most instances.