Background: Obesity is a strong predictor of fecundity and maternal obesity may well program semen quality during pregnancy, but to our knowledge, no published studies have evaluated this hypothesis.
Methods: From a Danish pregnancy cohort established in 1984-87, 347 out of 5109 sons were selected for a follow-up study conducted from February 2005 to January 2006. Semen and blood samples were analyzed for conventional semen characteristics and reproductive hormones and related to information on maternal pre-pregnant body mass index (BMI) that was available for 328 men. Of these, 34 were sons of underweight, and 25 sons of overweight, mothers.
Results: Inhibin B decreased with increasing maternal BMI (P = 0.04) and the point estimates for sperm concentration, semen volume, percent motile sperm, testosterone and FSH suggested an impaired reproductive status among sons of overweight mothers, but none of the trends were statistically significant.
Conclusions: The results suggest that there may be an effect of high maternal BMI on the sons' semen quality, but the study had only enough power to justify a critical evaluation of the hypothesis in a larger study.