Gynecology and Obstetrics Clinical Medicine (Dec 2022)
Analysis of factors related to early miscarriage after in vitro fertilization embryo transfer
Abstract
Aims: This research aims to explore the factors related to early spontaneous miscarriage after in vitro fertilization and embryo transfer (IVF-ET) pregnancy, and to provide guidance for improving pregnancy outcomes. Methods: We retrospectively analyzed the data for clinical pregnant women (2591 cycles) undergoing IVF-ET at the reproductive center of Peking University People’s Hospital from January 2017 to December 2018; This included 544 ET cycles and 2047 frozen embryo transfer cycles. The analysis of factors associated with early miscarriage in the overall population of IVF/intracytoplasmic sperm injection (ICSI) pregnancies (including fresh and thawing cycles) was performed. Results: The risk of early miscarriage in the 35–39 age group was 1.35 times higher than that in the <35 age group (OR = 1.35 [1.05,1.73], p = 0.02). In addition, the risk of early miscarriage was 3.88 times higher in the group ≥40 years old than in the group <35 years old (OR = 3.88 [2.68,5.62], p < 0.001). Endometrial thickness also affected the miscarriage rate; the early miscarriage risk with endometrial thickness ≥8.5 mm was 0.78 times than that of the <8.5 mm group (OR = 0.78 [0.62,0.98], p = 0.03). The early miscarriage rate during frozen embryo transfer was 1.48 times higher than that during fresh embryo transfer (OR = 1.48 [1.08,2.02], p = 0.01), while in the fresh cycle, the risk of early miscarriage with high-quality embryos was 0.5 times lower than that with non-high quality embryos (OR = 0.5 [0.27,0.9], p = 0.02). In the frozen cycle, the risk of early miscarriage in natural cycle transplantation was 0.73 times that in hormone replacement treatment (HRT) cycle transplantation (OR = 0.73 [0.54,0.97], p = 0.03) . Conclusions: Advanced age is an independent risk factor for early miscarriage, while endometrial thickness at the date of transplantation is an independent protective factor. The risk of early miscarriage in fresh-cycle transplanted embryos is significantly lower than that in frozen embryos, and the number of high-quality embryos in the fresh cycle lowers the miscarriage rate significantly. Natural cycle transplantation has a lower rate of early miscarriage than hormone replacement therapy.
