A new study published in the Journal of Clinical Endocrinology & Metabolism (JCEM) finds that women who are deficient in vitamin D are half as likely to conceive using in vitro fertilization compared with women without vitamin D deficiency.

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Vitamin D may boost production of good-quality eggs in the ovaries and improve the chances of embryos implanting successfully in the uterus.

Vitamin D is a steroid hormone that is produced in the skin as a consequence of exposure to the sun, and it can also be absorbed by eating certain foods. Vitamin D is essential for good bone health, but scientists are now becoming interested in the effect vitamin D may have on fertility.

Research has found that deficiency of vitamin D impairs fertility in rodents, although the role this deficiency may play in human reproduction has not previously been fully investigated.

To examine this further, researchers from Ospedale Maggiore Policlinico and the San Raffaele Scientific Institute in Milan, Italy, conducted a large study comparing in vitro fertilization outcomes between women with low levels of vitamin D and women with sufficient levels of vitamin D.

All of the women in the study had been referred to the Infertility Unit of the Fondazione Ca' Granda at Ospedale Maggiore Policlinico for in vitro fertilization (IVF) during 2012. The participants were comprised of 154 women who were vitamin D deficient (exhibiting less than 20 ng/ml of the hormone in their blood) and 181 women who had sufficient levels of vitamin D (more than 20 ng/ml).

Vitamin D levels in the blood of 30 ng/ml are recommended for general health.

The study found that women with sufficient levels of vitamin D were almost twice as likely to conceive, compared with the women who exhibited insufficient levels of vitamin D.

The researchers think that this improved fertility rate among the women with sufficient levels of the hormone could be due to the vitamin D boosting production of good-quality eggs in the ovaries and improving the chances of embryos implanting successfully in the uterus.

Largest study to investigate how vitamin D affects IVF ferility

"Our work is the largest study to date to examine how vitamin D affects fertility in women who are undergoing IVF," says one of the study's authors, Alessio Paffoni of the Ospedale Maggiore Policlinico. "We found that women who had sufficient levels of vitamin D were more likely to produce high-quality embryos and more likely to become pregnant than women who were deficient in vitamin D."

Paffoni continues:

"Although randomized clinical trials are needed to confirm the findings, our results certainly suggest that low levels of vitamin D contribute to infertility. Since vitamin D supplementation is an inexpensive and simple intervention with few relevant side effects, additional study in this area has the potential to markedly influence the way infertility is treated."

Recently, Medical News Today has looked at several other studies investigating the properties of vitamin D and the adverse consequences associated with a deficiency of the hormone.

These include a study from researchers in the UK that suggests a link between dementia and vitamin D deficiency. Another study published in JCEM also finds that vitamin D deficiency could increase the risk of schizophrenia.

Also, in June, two studies associated vitamin D deficiency with death from all causes and premature death.