A systematic review and meta-analysis of lifestyle and body mass index predictors of successful assisted reproductive technologies

Abstract

Objective: Lifestyle (smoking, drinking alcohol) and body mass index (BMI) predictors of successful outcomes in assisted reproductive technology (ART) treatments were examined in this meta-analysis.

Method: A bibliographic search was undertaken using six databases. The review was informed by PRISMA/MOOSE guidelines. Meta-analytic data were analysed using random effects models.

Results: We included 77 studies examining effects of BMI, smoking and drinking alcohol. Patients with a BMI< =24.9 were significantly more likely to achieve LB/pregnancy than with BMI> =25 OR = 1.219 (95% CI:1.128–1.319, z = 4.971, p < .001; I² = 53.779%, p = .001). Non-smokers were significantly more likely to achieve a LB or pregnancy than smokers OR = 1.457 (95% CI:1.228–1.727, z = 4.324, p < .001; I² = 51.883; p = .001). Meta-regression revealed the number of embryos transferred significantly moderated the effects of smoking on ART outcomes, and there was a trend indicating primary infertility and high BMI were also significant moderators. The evidence for drinking alcohol was inconclusive due to the small number of studies.

Conclusions: This meta-analysis confirms that ART treatment success can be predicted with lifestyle factors. Further, non-smokers’ relative odds of pregnancy/live birth increase as more embryos were transferred but there was a trend that the odds of pregnancy/live birth decrease with primary infertility and high BMI.

Keywords:

• Infertility
• IVF
• women’s health
• assisted reproductive technologies

Acknowledgements

The authors would like to acknowledge the help of Subarna Roy for retrieving articles.

Disclosure statement

The authors have no interests to declare.

Current knowledge on the subject

• Research evidence for the effect of BMI on ART outcomes are often inconsistent.

• Smoking has consistently been found to be detrimental to fertility outcomes but the effects of alcohol on ART outcomes is inconclusive.

• Further, there is a need to investigate whether life style and BMI factors moderate each other on ART outcomes.

What this study adds

• This large, comprehensive meta-analysis of published studies found consistent evidence that being overweight/obese and smoking significantly decreases the odds of achieving positive ART outcomes.

• The effects of alcohol on ART outcomes were not significant.

• Smoking is moderated by number of embryos transferred and there was some data to suggest primary infertility and high BMI was moderated by smoking.

Additional information

Funding

This research was funded by the British Academy small grant award [SG100026].