Impact of Obesity on In Vitro Fertilization (IVF) Outcomes: A Systematic Review

Obesity is a prominent health issue across the globe that causes negative reproductive consequences like decreased fertility. Even its effects on the success of in vitro fertilization (IVF) have drawn interest, with some studies indicating that BMI was linked to IVF failure. In this systematic review, we attempt to bring together the data regarding the impact of obesity on IVF outcomes. It also intends to quantify the adverse effects of female partner obesity on key IVF measures such as implantation, clinical pregnancy rate (CPR), live birth rate (LBR), and miscarriage rate (MR), and to understand the mechanism of these adverse effects in obese women. A literature search was undertaken in PubMed/Medline, PubMed Central, Cochrane Library, Science Direct, and MDPI for studies comparing the effects of obesity (BMI ≥ 30 kg/m²) on IVF results. These studies included randomized controlled trials, cohort studies, case studies, literature reviews, and case-control studies. From the databases, we were able to select 533 relevant articles. The studies were evaluated, eligibility standards were followed, and 13 papers were considered. We collected data, and analyses of implantation rates, CPR, LBR, and MR were narratively reviewed because the studies were heterogeneous. This review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the quality was assessed using the Cochrane Risk of Bias 2 scale for randomized trials and the Newcastle-Ottawa Scale for observational studies. A total of 13 studies, including participants, were included in the analysis. Obesity was consistently correlated with lower implantation, reduced CPR and LBR, and higher MR than women with normal BMI. To be precise, every five-unit increase in BMI was associated with a 5-7% reduction in CPR and LBR and a 9% rise in MR, underscoring the significant impact of obesity on IVF outcomes. In terms of mechanisms, metabolic disturbances in the oocytes, reduced endometrial response, and chronic inflammation were identified as the primary causes of these poor outcomes in obese women. In addition, interventions to reduce weight, such as diet and bariatric surgery, had an impact on the success of IVF. Obesity has a significant negative effect on IVF success, both in terms of oocyte quality and endometrial responsiveness. In overweight women who are seeking fertility treatment, weight control must be part of preconception treatment. However, further studies are needed to determine effective weight loss interventions and to better understand the mechanisms underlying IVF success in this group.