Elevated Body Mass Index in Donor Oocyte Recipients Does Not Affect Implantation of Euploid Embryos

Background: Obesity is a worldwide epidemic that has been shown to have serious implications on health outcomes. Regarding reproductive health, increased body mass index (BMI) reduces fertility and increases the time to conceive. It is unclear how excess weight in females affects the development of oocytes and embryos or the impact of implantation. Materials and Methods: This retrospective single-center study aimed to determine if overweight and obese oocyte recipients had similar pregnancy outcomes compared with healthy weight controls after the transfer of a single euploid frozen-Thawed embryo transfer (FET). Five hundred twenty-eight patients who underwent a transfer from 2016 to 2021 were included. The primary outcome studied was the clinical pregnancy (CP) rate. Secondary outcomes included live birth (LB) rate, biochemical pregnancy loss (BPL) rate, and clinical pregnancy loss (CPL) rate. Results: The overall CP rate was 54.9% and did not differ significantly among normal weight (n = 318), overweight (n = 129), and obese (n = 81) BMI categories (0.56 vs. 0.56 vs. 0.49, p = 0.56). There were no significant differences in LB rate (0.47 vs. 0.43 vs. 0.38, p = 0.33), BPL rate (0.14 vs. 0.09 vs. 0.11, p = 0.59), and CPL rate (0.15 vs. 0.21 vs. 0.18, p = 0.38) among BMI groups. Conclusions: Our findings provide support that BMI alone does not adversely alter endometrial receptivity and is not the cause of poor in vitro fertilization (IVF) outcomes in patients with increased BMI. These deleterious IVF outcomes might be to the result of diminished oocyte and/or embryo quality or other factors that have not yet been elucidated.