Lifestyle Program Increases Natural Pregnancy but Not Live Birth

A randomized controlled trial published in J Clin Endocrinol Metab evaluated whether a lifestyle intervention before and during fertility treatment improved outcomes among women with obesity and infertility or overweight with polycystic ovary syndrome (PCOS).

The Obesity-Fertility randomized controlled trial included 127 women aged 18 to 40 years who were treated at an academic fertility clinic. Eligible participants had infertility and obesity, defined as a body mass index of at least 30kg/m², or were overweight with PCOS, defined as a body mass index of at least 27kg/m². Randomization was stratified by PCOS status.

Women assigned to the intervention group received a 6-month lifestyle program before fertility treatment was added, and the intervention continued during fertility care. The program included individual follow-up with a dietitian and kinesiologist, along with group sessions. Women assigned to the control group received usual fertility care directly.

At 6 months, the intervention group had greater weight loss and waist-circumference reduction compared with the usual care group. The live-birth rate was 44.4% in the intervention group and 35.9% in the control group, corresponding to a risk ratio of 1.24 (P=.33). Clinical pregnancy rates were 52.4% and 37.5%, respectively, and natural pregnancy rates were 27.0% and 12.5% (P=.049).

The authors concluded that the lifestyle intervention did not increase the 18-month rate of pregnancies leading to live birth compared with usual care, but it did significantly increase natural pregnancy rates. They noted that lifestyle interventions are commonly recommended in this population, although randomized evidence has been limited and structured programs are not routinely integrated into many fertility clinics.

Source: Belan M, Giguère-Johnson M, Carranza-Mamane B, et al. Lifestyle intervention before and during fertility treatment in women with obesity or with overweight and PCOS—a RCT. J Clin Endocrinol Metab. 2026;111(6):e1643-e1652. doi:10.1210/clinem/dgaf660