The effect of a very short interpregnancy interval and pregnancy outcomes following a previous pregnancy loss

OBJECTIVE: We sought to assess the relationship between a short interpregnancy interval (IPI) following a pregnancy loss and subsequent live birth and pregnancy outcomes. STUDY DESIGN: A secondary analysis of women enrolled in the Effects of Aspirin in Gestation and Reproduction trial with a human chorionic gonadotropin-positive pregnancy test and whose last reproductive outcome was a loss were included in this analysis (n = 677). IPI was defined as the time between last pregnancy loss and last menstrual period of the current pregnancy and categorized by 3-month intervals. Pregnancy outcomes include live birth, pregnancy loss, and any pregnancy complications. These were compared between IPI groups using multivariate relative risk estimation by Poisson regression. RESULTS: Demographic characteristics were similar between IPI groups. The mean gestational age of prior pregnancy loss was 8.6 +/- 2.8 weeks. The overall live birth rate was 76.5%, with similar live birth rates between those with IPI <= 3 months as compared to IPI > 3 months (adjusted relative risk [aRR], 1.07; 95% confidence interval [CI], 0.98-1.16). Rates were also similar for periimplantation loss (aRR, 0.95; 95% CI, 0.51-1.80), clinically confirmed loss (aRR, 0.75; 95% CI, 0.51-1.10), and any pregnancy complication (aRR, 0.88; 95% CI, 0.71-1.09) for those with IPI <= 3 months as compared to IPI > 3 months. CONCLUSION: Live birth rates and adverse pregnancy outcomes, including pregnancy loss, were not associated with a very short IPI after a prior pregnancy loss. The traditional recommendation to wait at least 3 months after a pregnancy loss before attempting a new pregnancy may not be warranted.