Miscarriage risk in women with unexplained recurrent implantation failure after clinical pregnancy: a multicentre cohort
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Published on: August 4, 2021
Yina Hu1, Yiqi Liu2, Chenxi Zhao3
1Center for Reproductive Medicine, Jiangxi Key Laboratory of Reproductive Health, Jiangxi Maternal and Child Health Hospital, Jiangxi Branch of National Clinical Research Center for Obstetrics and Gynecology, Nanchang, China.
Research Question:
What is the impact of previous unexplained recurrent implantation failure (uRIF) on fertility outcomes in women achieving clinical pregnancy in subsequent embryo transfers?
Design:
This retrospective cohort study was conducted at three reproductive medicine centres in China from 2014 to 2021. Women who failed to conceive after three or more transfer cycles with four or more good-quality embryos comprised the uRIF group. Control participants were those achieving clinical pregnancy within their first or second transfer. Women with identifiable causes of implantation failure or miscarriage were excluded. Propensity score matching, multiple logistic regression and subgroup analyses were performed to adjust for potential confounders. The primary outcome was miscarriage rate.
Results:
Among 162,079 embryo transfer cycles screened, 53,531 women met the eligibility criteria. After matching, 1595 women were allocated to the uRIF group and 4785 to the control group. Miscarriage rates were comparable between groups (16.9% versus 15.9%; adjusted odds ratio [aOR] 1.06, 95% confidence interval [CI] 0.91-1.24), including early and late miscarriage. Ectopic pregnancy and live birth rates also showed no significant differences, while implantation rate remained lower in uRIF patients (67.6% versus 70.1%), as did multiple pregnancy rate (23.2% versus 26.5%; aOR 0.81, 95% CI 0.71-0.94). Subanalyses consistently showed similar miscarriage rates between groups for singleton and multiple pregnancies.
Conclusions:
In this multicentre retrospective cohort study, a history of uRIF was not associated with a higher risk of miscarriage when clinical pregnancy was achieved.
