Figure 2. Associations of Body Mass Index (BMI) in Women and Men With Adjusted Odds Ratios (ORs) of Subfertility.

Adjusted ORs (with 95% CIs) of subfertility (time to pregnancy or duration of actively pursuing pregnancy >12 months and assisted reproductive technology) associated with BMI categories. Odds ratios were derived from the exponentiated coefficients of the logistic regression models. An OR greater than 1 indicates increased odds of subfertility compared with the reference category (normal weight). Main analysis for women was adjusted for participant’s age, ethnicity, educational level, smoking, alcohol consumption, and parity. Main analysis for men was adjusted for participant’s age, ethnicity, educational level, smoking, and alcohol consumption (OR of underweight in men must be interpreted with caution due to the small sample size in this group). Several sensitivity analyses were performed, excluding episodes with assisted reproductive technology (eTable 11 in Supplement 1), excluding the top 5% observations of time to pregnancy correcting for the right-skewed distribution (eTable 12 in Supplement 1), including only first episodes of participants (eTable 13 in Supplement 1), and including partner’s BMI as a covariate (eTable 14 in Supplement 1).