Does weight loss in overweight or obese women improve fertility treatment outcomes? A systematic review

Abstract

SummaryThis systematic review assessed the effect of weight loss in overweight and/or obese women undergoing assisted reproductive technology (ART) on their subsequent pregnancy outcome. Weight losses achieved by diet and lifestyle changes, very--low--energy diets, non--surgical medical interventions and bariatric surgery translated into significantly increased pregnancy rates and/or live birth in overweight and/or obese women undergoing ART in 8 of the 11 studies reviewed. In addition, regularization of the menstrual pattern, a decrease in cancellation rates, an increase in the number of embryos available for transfer, a reduction in the number of ART cycles required to achieve pregnancy and a decrease in miscarriage rates were reported. There were also a number of natural conceptions in five of the six studies that reported this outcome. Non--surgical medical weight loss procedures and bariatric surgery induced the greatest weight losses, but their use, as well as that of very--low--energy diets, for weight loss prior to ART requires careful consideration. While the overall quality of the studies included in this review was poor, these results support the clinical recommendation of advising overweight and/or obese women to lose weight prior to ART. Prospective randomized controlled trials are required to establish efficacious evidence--based guidelines for weight loss interventions in overweight and/or obese women prior to ART treatment. Introduction Obesity has numerous health implications relating to fertility and is now the most common clinical risk factor encountered in obstetric practice [1]. Infertility in natural menstrual cycles has been shown to be almost three times higher in obese women (i.e. those with a body mass index [BMI] ≥ 30 kg m−2) [2, 3]. The positive relationship between BMI and time to pregnancy has been established in overweight and obese women with anovulation as well as in those with a regular menstrual cycle [4,5]. With the increasing prevalence of obesity worldwide, the number of obese women who are seeking assisted reproductive technology (ART) as a treatment for infertility is on the rise [6].Not only is it more difficult for overweight or obese women to conceive, pregnancy in overweight and obese women is associated with an increased risk of complications for both the mother and the fetus [7--9]. In addition to problems apparent during pregnancy or in the perinatal period, pre--pregnancy and gestational obesity may lead to a self--reinforcing vicious cycle of excessive weight gain and adiposity that is passed on from mother to successive offspring [10--12]. While the underlying mechanisms of such maternal obesity--induced programming remain unclear (and are possibly epigenetic), the hypothesis is a potentially important explanation for the rapid rise in obesity [11].While an increasing number of obese women are seeking ART, it is by no means an optimum solution for infertility in this population. Obesity has been found to impair ART outcomes in most, but not all studies, as recent...

Health Benefits of Long-Term Weight-Loss Maintenance

“…One small study suggested that there was no improvement in overall sexual function after LAGB in males and that erectile index and orgasmic function worsened when adjusted for time (164). The evidence supporting an effect of weight loss on the management of fertility issues is of relative low quality, but the overall results suggest a benefit (192). Studies to evaluate the effect of bariatric surgery on male fertility are needed (139).…”

Obesity and reproduction: a committee opinion

“…Preconception weight loss in obese women is also important to reduce morbidity from anesthesia-related surgical procedures, such as oocyte retrieval (124). To date, however, there is no strong evidence that preconception weight loss in women improves IVF-related pregnancy outcome (125), and the data are less clear in men. Nevertheless, weight loss is assumed to benefit fertility as it does for diabetes and CVD.…”

Physiological Aspects of Female Fertility: Role of the Environment, Modern Lifestyle, and Genetics

“…Several studies demonstrate the benefit of weight loss as part of a structured weight loss program upon the chance of conception for overweight women, and also as part of their IVF treatment (61,314). In a systematic review of 11 stud-ies that met the search criteria weight loss on the outcome of subsequent IVF treatment, losing weight by either diet and lifestyle changes (7 studies), nonsurgical medical interventions (1 study), or bariatric surgery (2 studies) led to a significant increase in the natural conception rate, an increase in the number of embryos available for transfer as well as the subsequent pregnancy rate, and a decrease in the miscarriage rate (314).…”

“…In a systematic review of 11 stud-ies that met the search criteria weight loss on the outcome of subsequent IVF treatment, losing weight by either diet and lifestyle changes (7 studies), nonsurgical medical interventions (1 study), or bariatric surgery (2 studies) led to a significant increase in the natural conception rate, an increase in the number of embryos available for transfer as well as the subsequent pregnancy rate, and a decrease in the miscarriage rate (314). Due to the difficulty in completing such studies, the overall quality of the studies was reported as weak, although all interventions led to significant improvements in pregnancy or live birth rates in overweight or obese women, with several studies reporting an improvement in spontaneous pregnancy rates.…”