Weight Loss Linked to Increase in Pregnancy Rates

MONDAY, Aug. 11, 2025 (HealthDay News) — For women with obesity, weight-loss interventions before in vitro fertilization (IVF) are associated with an increase in total pregnancy rates and in pregnancies resulting from unassisted conception, according to a review published online Aug. 12 in the Annals of Internal Medicine.

Moscho Michalopoulou, D.Phil., from the University of Oxford in the United Kingdom, and colleagues examined whether weight-loss interventions before IVF improve reproductive outcomes in a systematic review that included randomized controlled trials (RCTs) conducted in women with obesity identified from five electronic databases. Twelve RCTs were included, with 1,921 participants; seven of the trials had a high risk for bias.

The researchers found moderate certainty that pre-IVF weight loss interventions were associated with an increase in total pregnancy rates and pregnancies resulting from unassisted conception (risk ratios, 1.21 and 1.47, respectively); an uncertain effect was seen on pregnancies resulting solely from IVF. There was no association seen for weight-loss interventions with pregnancy weight-loss rates, while the effect on live birth rates was not clear.

“In conclusion, preconception weight loss in women with obesity seeking IVF increases the chances of pregnancy, especially through unassisted conception, which may negate the need for treatment, and does not seem to increase the risk for pregnancy loss,” the authors write.

Abstract/Full Text (subscription or payment may be required)

Editorial (subscription or payment may be required)