Advanced paternal age alone does not adversely affect pregnancy or live‐birth rates or sperm parameters following intrauterine insemination

PURPOSE: This study aimed to evaluate the effect of advanced paternal age on pregnancy outcomes and sperm parameters following intrauterine insemination (IUI). We used IUI data rather than assisted reproductive technology data, which might mask the effects of sperm impairments. METHODS: We retrospectively analyzed 1576 IUI cycles in women under 40 years old between April 2012 and May 2016 at the National Center for Child Health and Development in Japan. The main outcomes were clinical pregnancy and live birth. RESULTS: The mean male age was significantly lower in cycles that resulted in pregnancy compared with those without pregnancy (38.0 vs 39.1 years; P < 0.001), with a similar trend for live‐birth cycles. However, there was no relationship between advanced paternal age and pregnancy outcomes after adjusting for confounding factors and correlations within patients using generalized estimating equations, and the age of the female partner was the only factor affecting pregnancy rate. Furthermore, advanced paternal age had no effect on sperm parameters. CONCLUSIONS: Advanced paternal age alone does not adversely affect pregnancy or live‐birth rates or sperm parameters following IUI.