Up to 15% of couples are infertile and about 20% of infertility is unexplained by known causes. If you are trying to get pregnant or are having difficulty getting pregnant, a recent review paper should interest you.
Drs Elisabeth Lerchbaum and Barbara Obermayer-Pietsch of the Medical University of Graz in Austria published an authoritative review of vitamin D and fertility. They reviewed all the literature on the subject, test tube studies, animal data and human data.
They highlighted the following points:
- Both the vitamin D receptor (VDR) and the enzyme that turns 25(OH)D into a steroid hormone (1-hydroxylase) are present throughout the reproductive system of both males and females.
- Vitamin D increases production of sex steroids in both male and female laboratory animals.
- Severe vitamin D deficiency reduces fertility of male and female rats by up to 73%.
- Laboratory animals without the genes for the VDR and the 1-hydroxylase seldom reproduce.
- Some studies show that women with polycystic ovarian disease, which is associated with infertility, may have higher fertility rates with supplementation.
- In men, better sperm motility is associated with higher vitamin D blood levels.
- Supplementation with vitamin D increases men’s testosterone levels.
- Some studies show that women with higher levels are more likely to succeed with in vitro fertilization.
- Vitamin D supplementation of pregnant women (4,000 IU/day) resulted in a 50% lower rate of preterm delivery, a 25% reduction in infections of the mother, and a 30% decreased risk of complications of pregnancy.
- However, many women get pregnant who are vitamin D deficient.
As most infertility is due to endocrine problems or prior illness and resultant structural changes in the reproductive tract, they conclude,
“We want to emphasize the fact that in infertility cases drastic improvements in reproductive failure may not be achieved by vitamin D treatment alone. However vitamin D supplementation is a safe and cheap treatment, which might have some beneficial effects on human reproduction.”
The Vitamin D Council recommends that any couple thinking about conceiving a child should first get their vitamin D levels up to the natural range (50 ng/ml) for a year, maintaining that level during pregnancy, and ensure that the infant and later child is adequately supplemented throughout growth and development. We believe there is sufficient scientific evidence to suspect this will reduce the incidence of numerous pregnancy complications and later childhood diseases.