Publication:

Comparing the incidence of pre-eclampsia following freeze-all versus conventional in-vitro fertilization: a systematic review and meta-analysis of randomized controlled trials

In vitro fertilization (IVF) is commonly used to treat infertility, but its association with pre-eclampsia is well-documented. The freeze-all strategy in IVF has gained popularity, but its impact on the incidence of pre-eclampsia compared to conventional fresh embryo transfer remains uncertain. This systematic review and meta-analysis aimed to compare the incidence of pre-eclampsia in pregnancies following freeze-all versus conventional fresh embryo transfers in randomized controlled trials (RCTs). A comprehensive search was conducted across PubMed, Web of Science, Scopus, Medline, the Cochrane Library, and Google Scholar databases. A total of 611 records were identified and screened for suitability for inclusion in the quantitative synthesis. Data extraction and quality assessment were performed, and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated using fixed-effects models. Heterogeneity was assessed using Chi² and I² statistics. The meta-analysis included data from 7 RCTs, involving a total of 4,749 participants (2,434 in the freeze-all group and 2,315 in the conventional group). The pooled analysis revealed a significantly higher risk of pre-eclampsia in the freeze-all group, with an OR of 2.14 (95% CI 1.47, 3.11; p<0.0001). The heterogeneity among the studies was low (Chi square=5.88, df=6, p=0.44; I²=0%). This meta-analysis indicates that the freeze-all strategy in IVF is associated with a significantly higher risk of pre-eclampsia compared to conventional fresh embryo transfer. Clinicians should consider this increased risk when planning IVF treatments and counsel patients accordingly.