Vitamin D (Fertility Context)
Vitamin D is a fat-soluble prohormone. It is converted in the body to 25-hydroxyvitamin D, the circulating form measured to assess status, and then to 1,25-dihydroxyvitamin D, the active hormone that functions as a steroid hormone, binds vitamin D receptors (VDRs), and regulates immune function, inflammation, and reproductive biology. VDRs are expressed in the ovaries, endometrium, uterus, and spermatozoa, making adequate vitamin D status relevant across the full reproductive system.
Vitamin D deficiency is associated with reduced ovarian stimulation response in women with PCOS, lower live birth rates, and impaired endometrial receptivity. These findings come from observational studies. Randomized supplementation trials have not yet shown that correcting vitamin D deficiency raises live birth rates. In RRM and NeoFertility practice, vitamin D status is routinely assessed as part of preconception evaluation. Optimization targets are individualized under clinical guidance rather than applied as a universal threshold.
This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.