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Recent RCT discovers bolus dose of 50,000 IU vitamin D may increase fertility in women

Posted on: August 4, 2017   by  Riley Peterson & John Cannell, MD.


Female infertility is a condition which affects approximately 10% of women in the United States. Infertility occurs when a woman tries, unsuccessfully, to conceive a child for one year or longer. Occurrence of infertility is equally common between men and women.

The female reproductive system is heavily dependent on a few crucial hormones that regulate the ovarian cycle and ovulation. One key hormone in the process of ovulation is anti-Müllerian hormone (AMH), a regulatory hormone that plays important roles in both males and females across the life cycle. However, AMH is most significant during a woman’s reproductive years. When women reach sexual maturity, AMH regulates the response of the immature eggs in the ovaries to follicle stimulating hormone (FSH), making it a key player in the ovulation cycle. FSH is a regulatory hormone detrimental to the reproductive cycle of females. As menstruation begins, FSH levels increase and signal the ovarian follicles to begin egg maturation.

Research has found vitamin D is associated with fertility in couples attempting pregnancy. Additionally, vitamin D is known to regulate the levels of AMH and other reproductive tract functions in vitro. Researchers hypothesize that vitamin D levels may be correlated with AMH in women during ovulation; however, observational studies have not yet discovered this association. Additionally. low levels of AMH are commonly associated with infertility in women attempting pregnancy. Therefore, researchers recently evaluated the effect of a single, bolus dose of vitamin D on AMH levels in women during menstruation.

A total of 46 women of reproductive age with normal menstrual periods were included in the study. The researchers excluded women who were pregnant, consumed vitamin D supplements or used sunbeds. The women were randomly assigned to either receive a one-time dose of 50,000 IU vitamin D3 or a placebo pill after the onset of their menstrual period. Serum vitamin D levels and AMH levels were collected via blood draws at baseline, 1, 3 and 7 days following the administration of either the vitamin D supplement or the placebo pill.

This is what the researchers found:

  • Participant’s baseline vitamin D levels ranged between 4-46 ng/ml, with 40 of the 46 women having levels less than 30 ng/ml.
  • The vitamin D intervention group experienced a steady rise in serum AMH following their treatment (p = 0.001).
  • The average rise in AMH by the end of the seven-day trial was 3.3 pmol/L (p = 0.01).
  • In both the intervention and the placebo group, the women with lower initial AMH values exhibited greater increase in AMH (p = 0.005).

The researchers concluded:

“This study reports that an acute rise in Vit D status in women leads to changes in circulating AMH that are consistent with animal and human in vitro studies… clinical studies are needed to determine the relevance of Vit D regulation of AMH production to ovarian pathologies and to the fertility of women with depleted ovarian reserve.”

This study possessed several strengths, including the RCT design and matched baseline characteristics.  However, the study population was relatively small and the study duration was very short. The researchers stated that larger trials are needed to determine whether or not reversal of vitamin D deficiency would reveal clinically significant changes in AMH status in women with impaired fertility.


Peterson, R. & Cannell, JJ. Recent RCT discovers bolus dose of 50,000 IU vitamin D may increase fertility in women, 7/2017.


Dennis, N. et al. Acute Supplementation with High Dose Vitamin D3 Increases Serum Anti-Müllerian Hormone in Young Women. Nutrients, 2017.

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