Abstract
BACKGROUND: Male obesity has been related to poor semen quality and may also have a negative effect on assisted reproductive technologies (ART) outcomes. Whether male waist circumference (WC), as a measure of central obesity, impacts a couple's fertility independently of BMI is unclear. OBJECTIVES: To examine the associations of male WC with semen quality and couples' outcomes of infertility treatment with ART. METHODS: Couples presenting to the Massachusetts General Hospital Fertility Center were invited to participate in the study. Between 2009 and 2019, 269 males provided 671 semen samples and 176 couples underwent 317 ART cycles. Height, weight, and WC were measured on site. We analyzed the association of male WC with semen quality and pregnancy outcomes using cluster-weighted regression models to account for repeated observations while adjusting for potential confounders. Models were also stratified by male BMI (<25 kg/m2 compared with ≥25 kg/m2). RESULTS: The median male age, WC, and BMI were 36.1 years, 96.0 cm, and 26.8 kg/m2, respectively. A 5-cm increase in WC was associated with a 6.3% (95% CI, 2.1-10.5%) lower sperm concentration after adjustment for potential confounders, including BMI. Male WC was also inversely related to the probability of achieving a live birth. For each 5-cm increase in male WC, the odds of a live birth per initiated cycle decreased by 9.0% (95% CI, 1.1%-16.4%) after accounting for several anthropometric and demographic characteristics of both partners. These associations were stronger among males in the normal BMI category (<25 kg/m2) than among overweight or obese males. CONCLUSIONS: A higher male WC may be an additional risk factor for poor outcomes of infertility treatment, even after accounting for male and female partner BMIs, particularly in couples where the male partner has a normal BMI.