Effectiveness of lifestyle intervention in subgroups of obese infertile women: a subgroup analysis of a RCT

STUDY QUESTION: Do age, ovulatory status, severity of obesity and body fat distribution affect the effectiveness of lifestyle intervention in obese infertile women? SUMMARY ANSWER: We did not identify a subgroup in which lifestyle intervention increased the healthy live birth rate however it did increase the natural conception rate in anovulatory obese infertile women. WHAT IS KNOWN ALREADY: Obese women are at increased risk of infertility and are less likely to conceive after infertility treatment. We previously demonstrated that a 6-month lifestyle intervention preceding infertility treatment did not increase the rate of healthy live births (vaginal live birth of a healthy singleton at term) within 24 months of follow-up as compared to prompt infertility treatment in obese infertile women. Natural conceptions occurred more frequently in women who received a 6-month lifestyle intervention preceding infertility treatment. STUDY DESIGN, SIZE, DURATION: This is a secondary analysis of a multicentre RCT (randomized controlled trial), the LIFEstyle study. Between 2009 and 2012, 577 obese infertile women were randomly assigned to a 6-month lifestyle intervention followed by infertility treatment (intervention group) or to prompt infertility treatment (control group). Subgroups were predefined in the study protocol, based on frequently used cut-off values in the literature: age (>= 36 or = 35 or = 0.8 or