Anogenital distance, male factor infertility and time to pregnancy

Anogenital distance (AGD), the distance between the anus and genitals, is in rodents a well-established marker of early androgen action and has been suggested to be so in humans as well. Thus, a link between human AGD and semen quality and potentially fecundity may exist.

The aim of this study was to assess the association between AGD and male factor infertility and among proven fertile men also time to pregnancy (TTP).

All included men were recruited from and examined at Copenhagen University Hospital - Rigshospitalet, Denmark (N = 388). Men with impaired semen quality were included from infertile couples (N = 128), and men with naturally conceived pregnant partners were invited to participate when their partners had their routine second trimester examination (N = 260). All men underwent a physical examination, completed a questionnaire (including TTP for the fertile men), delivered a semen sample and had a blood sample drawn. The primary exposure was AGD_AS measured from the centre of the anus to the posterior base of the scrotum. Associations between AGD and fertility status as well as between AGD and TTP among the fertile men were calculated using multiple logistic regression adjusted for covariates.

AGD did not show a statistically significant association with fertility status. In adjusted logistic regression models, the odds of infertility per 1 cm increase in AGD_AS were 1.02 (95% confidence interval [CI]: 0.88; 1.19). Among fertile men, a 1-cm increase in AGD_AS was associated with an 8% non-statistically significantly reduced odds of having a longer (>3months) TTP (adjusted odds ratio (OR) = 0.92, 95% CI: 0.76-1.11).

Our study showed that the clinical application of AGD as a predictor of fertility and fecundity seems to be limited as no associations were observed between AGD and fertility status, nor was the decreased risk of experiencing a longer TTP with longer AGD_AS statistically significant.