Vitamin D plays a role in reproductive capacity. Recently, several investigators have demonstrated higher IVF pregnancy rates in vitamin D replete women. Adjusting for age and number and quality of embryos transferred among non-Hispanic whites, the odds of pregnancy were four times higher in vitamin D replete versus deficient patients. Live birth rates mirrored pregnancy rates. Vitamin D status was not associated with ovarian stimulation parameters or with markers of embryo quality, suggesting its effect may be mediated through the endometrium.
The presence of the vitamin D receptor (VDR) in many tissues along the female reproductive axis, including the pituitary, ovary, uterus and placenta, suggests that vitamin D is an important regulator of the female reproductive system. The active form of vitamin D (1,25 dihydroxyvitamin D3 or calcitriol), is essential in the production of estrogen, integrally involved in embryo implantation and is important to regulate immune response at the maternal–fetal interface.