First-Trimester Vaginal Bleeding as a Marker of Unfavorable Pregnancy Outcomes

First-trimester vaginal bleeding occurs in as many as 25% of pregnancies. Does this event predict other pregnancy complications? In a retrospective cohort study, Danish investigators evaluated the association between first-trimester bleeding and risk for complications later in the same pregnancy or in a second pregnancy. Data were extracted from a national registry of all singleton births from 1978 through 2007. Outcomes were preterm delivery, preterm premature rupture of membranes, fetal growth, stillbirth after 20 weeks' gestation, placental abruption, and hypertensive pregnancy disorders.

First-trimester bleeding was associated with higher risk for preterm delivery during gestational weeks 32 through 36 (3.6% without bleeding vs. 6.1% wit…