Lifestyle intervention before and during fertility treatment in women with obesity or with overweight and PCOS-a RCT

Clinical Snapshot

Key Findings

• P Value: Not reported for primary outcome (CI crosses 1.0)

• Effect Size: Risk ratio 1.24 for live birth (non-significant)

• Primary Outcome: Live birth rate within 18 months: 44.4% (IG) vs 35.9% (CG)

• Nnt Or Sensitivity: Natural pregnancy NNT = 7 (based on 27.0% vs 12.5% rates)

• Confidence Interval: 95% CI 0.81-1.90

Clinical Application

Requires multidisciplinary team (dietician, kinesiologist) and 6-month pre-treatment period which may delay fertility care Relevant to Australian fertility clinics; lifestyle interventions align with RACGP obesity guidelines; may reduce PBS-funded ART utilisation through increased natural conception Women with obesity and infertility seeking fertility treatment in tertiary care settings

Abstract

CONTEXT: Lifestyle interventions are recommended for women with obesity and infertility, but trial evidence is scarce, and studies have not investigated interventions that continue during fertility treatment. OBJECTIVE: Evaluate effectiveness of a lifestyle intervention compared with usual care on fertility outcomes in women with obesity and infertility. DESIGN: The Obesity-Fertility randomized controlled trial (RCT), at an academic fertility clinic, included 127 women aged 18 to 40 years with infertility and obesity (body mass index ≥30 kg/m2, or ≥27 kg/m2 with polycystic ovary syndrome [PCOS]), excluding those unlikely to conceive naturally. The intervention group (IG) received a 6-month lifestyle intervention alone (individual follow-up with a dietician and kinesiologist, and group sessions) before adding fertility treatments. The control group (CG) received usual fertility care directly. Rate of live birth conceived within 18 months of randomization was analyzed. RESULTS: Compared to CG, the IG lost more weight (-3.21% ± 4.73% vs -0.40% ± 3.66%, P = .003) and waist circumference (-2.62 ± 4.46 cm vs -0.23 ± 3.81 cm, P = .01) at 6 months. The live-birth rate was 44.4% in the IG (n = 63) vs 35.9% in the CG (n = 64) (risk ratio [RR] = 1.24 [95% CI 0.81-1.90]). In IG vs CG, clinical pregnancy rates were 52.4% vs 37.5% (RR = 1.40 [0.94-2.07]) and natural pregnancy rates were 27.0% vs 12.5% (RR = 2.16 [1.01-4.64]). CONCLUSION: Compared with usual care, a lifestyle intervention alone for 6 months and then combined with fertility treatments did not increase the 18-month rate of pregnancies leading to a live birth, but significantly increased natural pregnancy rates, potentially reducing the need for costly assisted reproduction in this population.

References

1. 1.Belan, M., Giguère-Johnson, M., Carranza-Mamane, B., Pesant, M.-H., AinMelk, Y., Langlois, M.-F., Lavoie, H., Greenblatt, E. M., Laredo, S., Sagle, M., Waddell, G., Jean-Denis, F., & Baillargeon, J.-P. (2026). Lifestyle intervention before and during fertility treatment in women with obesity or with overweight and PCOS-a RCT. The Journal of Clinical Endocrinology and Metabolism. https://doi.org/10.1210/clinem/dgaf660