Vitamin D is a hormone that plays an important role in sustaining strength in bones and muscles, and for overall health. The main source of vitamin D is from the sun and small amounts can be obtained through food such as fatty fish, eggs, margarine and some cereals. 

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Vitamin D supplementation is recommended for women who are deficient in vitamin D (levels <50nmol/L) in the pre-conception period and during pregnancy. Vitamin D supplementation reduces the risk of small-for-gestational-age babies and impaired fetal skeletal development. 

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In the last decade, numerous studies underline that vitamin D is involved in the modulation of the reproductive process in women. Increasing evidence from several observational studies suggests that vitamin D might have a regulatory role in several PCOS-associated symptoms. It has also been said that Vitamin D may also be involved in the  pathogenesis of endometriosis due to its immunomodulatory and anti-inflammatory properties, although high quality large randomized clinical trials are needed to better evaluate the effect of vitamin D supplementation on female fertility.

 

Recent studies however have found that  there is an association between vitamin D status and reproductive treatment outcomes achieved in women undergoing assisted reproduction. Women undergoing assisted reproduction  who are replete in vitamin D have a higher live birth rate than women who are vitamin D deficient or insufficient.

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If you are trying to conceive and have a vitamin D deficiency, identified by a blood test, it is recommended that you start a supplement, as directed by your doctor.