P-508 The adverse effect of a previous late miscarriage on the subsequent pregnancy outcomes: a retrospective cohort study across more than ten years

Abstract

Abstract Study question To explore whether a previous late miscarriage (LM) has a prognostic impact on the subsequent pregnancy outcomes in in-vitro fertilization (IVF) women. Summary answer Women who had a LM for unexplained factor or cervical factor following first embryo transfer had a significantly poor pregnancy prognosis after the subsequent transfer. What is known already It has been reported that a history of early miscarriages is significantly associated with poor pregnancy outcomes. However, whether and how previous LM might influence future pregnancy outcomes still remain unclear. Study design, size, duration A retrospective cohort study was performed among 1072 infertile women who had a LM following the first embryo transfer from January 2008 to December 2020 at Center for Reproductive Medicine, Shandong University. Participants/materials, setting, methods 1072 infertile women who had a late miscarriage following first embryo transfer were grouped by the causes, 458 women with unexplained factor (unLM), 146 women with fetal factor (feLM), 412 women with cervical factor (ceLM), 56 women with trauma factor (trLM). Subgroup analysis and binary logistic regression were performed to evaluate the associations between late miscarriages with different causes and subsequent pregnancy outcomes. Main results and the role of chance Compared with general IVF population, the early miscarriage rate was significantly higher in the unLM group [8.28% vs 13.47%, adjusted OR (95%CI): 1.596(1.119-2.276), P=0.01]. Further, women with a unLM or ceLM had a dramatically elevated risk of recurrent late miscarriage [for unLM:4.24% vs 9.43%, adjusted OR (95%CI): 1.907(1.237-2.939), P=0.003; for ceLM: 4.24% vs 15.53%, adjusted OR (95%CI): 2.682(1.820-3.952), P=0.000] and a consequently reduced frequency of live birth [for unLM: 49.96% vs 43.01%, adjusted OR (95%CI): 0.746(0.612-0.908), P=0.004; for ceLM: 49.96% vs 38.59%, adjusted OR (95%CI): 0.611(0.494-0.756), P=0.000]. Limitations, reasons for caution This study was limited by the retrospective design from a single center and the sample size in feLM and trLM group is small. Further studies are needed to verify our results and ascertain the mechanisms underlying the reported associations. Wider implications of the findings Only one previous late miscarriage resulted from unexplained factor or cervical factor was significantly associated with a higher risk of miscarriage and a lower live birth rate after subsequent embryo transfer. Women with only one late miscarriage should be informed the great risk and given intense surveillance during subsequent pregnancy. Trial registration number not applicable