Excess weight in mothers has long been linked to fertility challenges, as high body fat disrupts two key hormones vital for ovulation in women with a BMI over 30. Less explored until now is the father's role. A comprehensive study by researchers from the U.S. National Institutes of Health (NIH), published in Human Reproduction, reveals that couples where both partners are obese require 55% to 59% more time to conceive.
Conducted from 2005 to 2011, the study tracked 501 couples over 18 from Michigan and Texas. Participants were grouped by BMI: 'class 1 obesity' (30-34.9, moderate) and 'class 2 obesity' (35+, severe). Couples were monitored until pregnancy or up to one year postpartum. Women logged menstrual cycles, intercourse, and pregnancy tests, enabling precise comparisons of conception times.
Findings showed severely obese couples faced substantially longer waits—an extra 55% on average, rising to 59% after adjusting for factors like age, smoking, and activity levels. This mirrors delays seen in medically assisted reproduction (PMA/IVF).
Experts now recommend weight loss for both partners in obese couples seeking pregnancy to improve chances.
