Bleeding in pregnancy increases risks in current/future pregnancies

July 1, 2010

Vaginal bleeding during the first trimester of a first pregnancy without miscarrying not only increases the risk for complications later in the pregnancy, but also in future pregnancies, according to study results.

Vaginal bleeding during the first trimester of a first pregnancy without miscarrying not only increases the risk for complications later in the pregnancy but also in future pregnancies, according to the results of a retrospective, registry-based cohort study conducted in Denmark.

Researchers identified 782,287 women delivering in Denmark from 1978 to 2007 with a first singleton pregnancy and 536,419 first and second singleton pregnancies.

They found that first-trimester bleeding increased the risk for delivery during weeks 32 to 36 from 3.6% to 6.1% (odds ratio [OR], 1.65; 95% confidence interval [CI], 1.57-1.77) and almost tripled the likelihood of delivery during weeks 28 to 31, from 0.3% to 0.9% (OR, 2.98; 95% CI, 2.50-3.54). It also raised the risk for placental abruption by more than 40%, from 1.0% to 1.4% (OR 1.48; 95% CI, 1.30-1.68).

Lykke JA, Dideriksen KL, Lidegaard O, Langhoff-Roos J. First-trimester vaginal bleeding and complications later in pregnancy. Obstet Gynecol. 2010;115(5):935-944.