The impact of unexplained spontaneous miscarriage history on cycle outcomes in patients undergoing in vitro fertilization: an analysis of 6535 patients.

Abstract

Objective: To investigate whether the previous spontaneous miscarriages affect the cycle outcomes in in vitro fertilization and embryo transfer (IVF-ET).

Methods: Comparisons were made on the cycle characteristics and outcomes between patients (underwent their first IVF-ET cycles between January 2018 and June 2022) without (Group A) and with (Group B) spontaneous miscarriage histories. Multiple regression analysis was performed to adjust for other possible confounders of cycle outcomes.

Results: In controlled ovarian stimulation cycles, the rate of viable embryos per oocyte in group A was higher than that in group B (0.40 ± 0.26 vs. 0.38 ± 0.27, p = 0.006). Multiple linear regression analysis confirmed that the previous miscarriage history was negatively associated with the oocyte utilization rate (p = 0.002). Moreover, in ET cycles, no statistical difference was observed regarding the miscarriage rate between the two groups (p = 0.497), while Group B presented with lower clinical pregnancy rate (46.1% vs. 42.3%, p = 0.006), lower ongoing pregnancy rate (40.5% vs. 37.0%, p = 0.009) and lower live birth rate (38.5% vs. 35.0%, p = 0.009). Further binary logistic regression analysis demonstrated that the previous miscarriage history had no significant effect on these pregnancy outcomes.

Conclusions: For patients receiving IVF-ET treatment, a miscarriage history is related to a lower oocyte utilization rate. However, there was no association between previous history of miscarriage and the pregnancy outcomes (e.g. miscarriage rate, pregnancy rate, live birth rate), once the patients had acceptable embryos for later transfer.