First-trimester bleeding and twin pregnancy outcomes after in vitro fertilization.

OBJECTIVE:To examine the association between first-trimester bleeding and live-birth rates in twin pregnancies conceived with in vitro fertilization (IVF). DESIGN:Retrospective cohort study. SETTING:Academic infertility practice. PATIENT(S):Women with two gestational sacs on first-trimester ultrasound after transfer of fresh embryos derived from autologous oocytes between January 1, 1999, and December 31, 2010. INTERVENTION(S):None. MAIN OUTCOME MEASURE(S):Live-birth rate. RESULT(S):Sixty-five women reported vaginal bleeding, and 288 did not. The baseline characteristics were similar between the two groups, except for an increased prevalence of subchorionic hematoma in women with first-trimester vaginal bleeding (26.2% vs. 1.7%). Live-birth rates were similar between women with bleeding and those with no bleeding (87.7% vs. 91.7%, adjusted odds ratio [OR] 0.73; 95% confidence interval [CI], 0.31-1.73). Two hundred eighty-eight women gave birth to live twins. Among the women who delivered twins, those with first-trimester bleeding had an increased risk of low birth weight of at least one twin (75.0% vs. 59.7%). The association between bleeding and low birth weight persisted after controlling for possible confounders with logistic regression (adjusted OR 2.33, 95% CI, 1.14-4.74). CONCLUSION(S):Live-birth rates are high in IVF twin gestations, regardless of the presence of first-trimester bleeding. Among women giving birth to IVF twins, however, first-trimester bleeding is associated with increased odds of low birth weight.