Losing weight before IVF associated with higher rates of pregnancy
A systematic review and meta-analysis of weight loss interventions before in vitro fertilization (IVF) didn't find a significant increase in pregnancies from IVF, but more patients got pregnant without assistance if they underwent a weight loss program.
Weight loss interventions before in vitro fertilization (IVF) could increase the chances of pregnancy, especially in unassisted conception, although the effect on live births was unclear, a meta-analysis concluded.
Researchers reviewed 12 randomized controlled trials with 1,921 patients conducted in 1980 to 2025. Inclusion criteria included studies conducted on women at least 18 years old with a body mass index (BMI) of 27 kg/m2 or greater who were seeking IVF with or without intracytoplasmic sperm injection treatment for infertility. Participants were typically in their early 30s with a median baseline BMI of 33.6 kg/m2. Outcomes of interest included number of participants achieving pregnancy without IVF (unassisted pregnancy), with IVF (treatment-induced pregnancy), and live births. The findings were published Aug. 12 by Annals of Internal Medicine.
Weight loss interventions studied included low-energy diets, an exercise program accompanied by healthy eating advice, and pharmacotherapy accompanied by diet and physical activity advice.
Overall, there was moderate certainty that pre-IVF weight loss interventions were associated with an increase in total pregnancy rates (risk ratio [RR], 1.21 [95% CI, 1.02 to 1.44]; 11 studies) and pregnancies resulting from unassisted conception (RR, 1.47 [95% CI, 1.26 to 1.73]; 10 studies), whereas the effect of weight loss on pregnancies resulting solely from IVF was uncertain. Weight loss interventions were not associated with pregnancy loss (RR, 1.05 [95% CI, 0.98 to 1.13]; eight studies; moderate certainty), but their effect on live birth rates was unclear (RR, 1.15 [CI, 0.95 to 1.40]; nine studies; very low certainty).
The researchers noted that more study is needed on the different weight loss interventions, particularly those known to achieve greatest weight loss, such as low-energy total diet replacement programs.
An editorial added that the study authors “highlight for future investigators the need for studies that include outcomes, including pregnancy loss and live birth, for both medically assisted and unassisted pregnancies. Future studies should also aim to define the optimal time frame and BMI targets for weight loss before fertility assistance. Finally, studies of the cost-effectiveness of fertility interventions are needed to help shape policies that best serve our patients.”