The Impact of Adverse Pregnancy Events in the Initial Cycle on Subsequent Pregnancy Outcomes

Abstract

Abstract Context Evidence is accumulating on the impact of previous adverse pregnancy events on future fertility in natural conceptions. However, there is limited knowledge on whether an ectopic pregnancy (EP) or miscarriage after an initial in vitro fertilization (IVF) cycle affects the subsequent outcomes. Objective To investigate the effect of first IVF outcomes (miscarriage, EP, and no pregnancy) on second cycle outcomes based on a freeze-all strategy. Methods Retrospective cohort study at a university-affiliated IVF center. This study involved 16 479 women who had undergone 2 complete frozen embryo transfers (FETs) and who were classified into 3 groups based on first FET outcomes. The main outcome measure was live birth rate (LBR). Results After correcting for confounders, the LBR after the second FET was similar between women who suffered an EP and those who had no pregnancies in their first FET cycles (adjusted odds ratio [aOR] 1.03; 95% CI 0.83-1.28). However, women who experienced a miscarriage vs those with no prior pregnancy in the first FET had significantly higher LBR in their second cycles (aOR 1.33; 95% CI 1.20-1.48). The LBR after the second FET was similar between the previous EP and miscarriage groups (aOR 1.24; 95% CI 0.98-1.58). Similar results were found in propensity score matching models, supporting the robustness of the main findings. Conclusion Women who had a miscarriage in the first FET cycle had a higher chance of achieving live births in the subsequent treatment cycle than those who had no pregnancy in the initial cycle. Furthermore, it was found that an EP resulting from the first treatment cycle did not negatively impact reproductive outcomes in the next FET cycles.