Does contemporary ART lead to pre-eclampsia? A cohort study and meta-analysis

Purpose Recent publications suggested that the risk for pre-eclampsia (PE) is higher with frozen-thawed embryo transfers (FETs) compared to fresh transfers (IVF-ETs). These studies were based on old data that reflects outdated practices. In this paper, we wanted to assess the incidence of PE in current assisted reproductive technology (ART) practice. Methods In this cohort study, we present the incidence of PE in all births in the province of Ontario, Canada, for the years 2013-2017 for FET, IVF-ET, and natural conceptions (NC). We also compare our findings to previous studies in a meta-analysis that includes over 4 million births. Results The results of our study show that contemporary practice of ART results in comparable risk for PE between FET and IVF-ET; however, the risk is higher than NC. Conclusion Current ART practice is associated with a lower risk for PE in frozen embryo transfer; this RR can be further attenuated by using ovulatory endometrial preparation for FETs.