Background: Vitamin D (Vit D) is important for the regulation of reproductive physiology. In humans, maternal Vit D deficiency has been implicated in several reproductive- and pregnancy-related disorders. Very few data are available regarding the Vit D status in male partners of couples attempting pregnancy. This observational study (IRB Prot. N. 078/13) aimed to evaluate whether low Vit D serum levels in males might decrease the rate of successful conception in couples attempting pregnancy.
Methods: Male and female partners of infertile couples (n = 102) were classified into 2 GROUPS according to normal (≥30 ng/ml) or low (below 30 ng/ml) serum Vit D levels in male partners. Semen analysis was performed in each male participant based on the WHO reference criteria. The female partners of both groups were subjected to 3 consecutive cycles of gonadotropin-induced mono-ovulation. The main outcome measures included the clinical pregnancy rate, delivery per patient and per cycle, and miscarriage rate between the 2 groups evaluated at the end of the three-month period of the study.
Results: In male partners of both groups, standard semen analysis did not highlight substantial differences in sperm concentration, sperm progressive motility, or typical form. The pregnancy rates per patient and per cycle and delivery rates per patient and per cycle were all significantly higher (p< 0.05) in couples with normal Vit D levels.
Conclusions: These results suggest the existence of a relationship between male Vit D serum levels and semen ability to begin a pregnancy during cycles of timed vaginal intercourse.