Study finds weight loss before IVF may boost pregnancy rates

Reproductive outcomes may be improved by weight loss prior to in vitro fertilization (IVF), according to a recent study published in the Annals of Internal Medicine.¹

The results highlighted increased pregnancy success in women with pre-IVF weight loss, especially in unassisted conception. However, live birth outcomes were not available.¹

“Further high-quality clinical trials testing different weight loss interventions, particularly those known to achieve greatest weight losses (e.g. low-energy total diet replacement programs) are needed,” wrote investigators.¹

Assessing reproductive outcomes

The study was conducted to assess reproductive outcomes following pre-IVF weight loss.² Five electronic databases were search for randomized controlled trials (RCTs) including women with obesity who were offered weight loss prior to IVF. Those published through May 27, 2025, were eligible for inclusion.

Low-energy diets, an exercise program alongside healthy eating advice, and pharmacotherapy alongside diet and physical activity device were considered as weight loss interventions. All participants were seeking IVF with or without intracytoplasmic sperm injection treatment for infertility.²

RCTs underwent dual independent screening, with those included having relevant data extracted and undergoing assessment for risk of bias. Pregnancy and live birth rates were reported as the primary outcomes.²

There were 1921 participants across 12 RCTs included in the final analysis. These patients were aged at least 18 years old and had a body mass index (BMI) of 27/kg2.¹ They were often in their early 30s, and the median BMI was 33.6 kg/m2.

Pregnancy and live birth outcomes

Of RCTs, 7 had a high risk of bias.² However, an association with moderate certainty between weight loss prior to IVF and total pregnancy rates was reported, with a risk ratio (RR) of 1.21 from 11 studies.

Similarly, an RR of 1.47 across 10 studies was reported for pregnancy following unassisted conception. However, there was not certain evidence about the impact on pregnancies from IVF alone.²

The RR for pregnancy loss with moderate certainty across 8 studies was 1.05 from weight loss interventions, indicating no significant impact. Similarly, an RR of 1.15 was reported for live birth rates across 9 studies, but the certainty of evidence was very low, making the impact of weight loss interventions on this outcome unclear.²

Overall, the data indicated increased odds of pregnancy, especially without assisted conception, from weight loss interventions prior to IVF. However, investigators noted the study was limited by small study sizes, high risk of bias, and heterogeneity.²

Public support for IVF

The demand for adequate IVF care has been indicated by a 2024 survey showing increased public support for this method of conception.³ Of respondents, 67% expressed a belief that IVF coverage should be offered by health insurance plans, with only 7% expressing opposition.

Investigators highlighted barriers to IVF coverage such as limited access among military service members and coverage only being provided to federal employees by a few available insurance plans. The American Society for Reproductive Medicine recommended patients with regular, unprotected intercourse and no known etiology for infertility undergo evaluation.³

References

1. Losing weight before IVF may increase chance of pregnancy. American College of Physicians. August 11, 2025. Accessed August 15, 2025. https://www.eurekalert.org/news-releases/1093687
2. Michalopoulou M, Ann Jebb S, Hobson A, et al. The effect of weight loss before in vitro fertilization on reproductive outcomes in women with obesity: a systematic review and meta-analysis. Annals of Internal Medicine. 2025. doi:10.7326/ANNALS-24-01025
3. Krewson C. Survey shows growing support for IVF coverage in US health care. Contemporary OB/GYN. April 25, 2025. Accessed August 15, 2025. https://www.contemporaryobgyn.net/view/survey-shows-growing-support-for-ivf-coverage-in-us-health-care.