The effect of weight loss interventions for obesity on fertility and pregnancy outcomes: a systematic review and meta-analysis

Bonnie R. Boyle* (Corresponding Author), Andrew D. Ablett, Christiantus Ochi, Jemma Hudson, Laura Watson, Diayne Rauh, Alison Avenell

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


Background: Weight loss could improve fertility, perhaps by reducing insulin resistance.
Objectives: To assess the effect of weight loss interventions on fertility in women with obesity not recruited because of known infertility.
Search strategy: Three databases 1966-2020, trial registry.
Selection criteria: RCTs with ≥1 year follow-up, with mean cohort BMI ≥30kg/m2.
Data collection and analysis: Systematic review and meta-analysis. Primary outcome was pregnancy. Secondary outcome was weight change.
Main results: We identified 27 RCTs (5938 women). Weight loss interventions showed no statistically significant increase in pregnancies compared to control interventions (24 trials, 97 women with pregnancy; risk ratio (RR) 1.43, 95% confidence interval (CI) 0.91 to 2.23); weight change (mean difference (MD) -2.36kg, n = 21 trials, 95% CI -3.17 to -1.55). Compared with low-fat diets, very-low-carbohydrate diets showed no statistically significant effect on women with pregnancyies, (3 trials, 14 women with pregnancy; RR 1.37, 95% CI 0.49 to 3.84) or weight change (MD -0.32kg, 95% CI -3.84 to 3.21).
Conclusions: Diet-based weight loss interventions for women with obesity not recruited because of infertility were effective at producing long term weight loss. Effects on fertility were not statistically significant, but few trials provided data. Weight loss trials should routinely collect fertility outcomes.
Original languageEnglish
Pages (from-to)335-342
Number of pages8
JournalInternational Journal of Gynecology and Obstetrics
Issue number2
Early online date9 Dec 2022
Publication statusPublished - May 2023

Bibliographical note

Open Access via the Wiley OA agreement.
We thank Paul Manson, University of Aberdeen Health Services Research Unit, for his help with the literature search. No external funding was required. The Health Services Research Unit is funded by the Chief Scientist Office of the Scottish Government Health and Social Care Directorates.

Data Availability Statement

Data available in article supplementary material.


  • fertility
  • low-fat diet
  • obesity
  • pregnancy
  • reducing diet
  • very-low-carbohydrate diet
  • weight loss


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