Vitamin D improves birth rates in women with polycystic ovary syndrome

This study explored the impact of vitamin D on women with polycystic ovary syndrome (PCOS) who were having ovulation induced (a procedure which encourages egg production to improve the chances of pregnancy). The study concluded that pregnancy outcomes were connected with vitamin D levels.

Nearly 10% of women of reproductive age in the United States have difficulty getting pregnant due to ovulation issues. PCOS is the most common cause of ovulation problems. In PCOS, hormone levels are unbalanced. It often causes infertility and leads to couples seeking help to get pregnant.

Vitamin D is essential for good health, particularly bone health. Deficiency of this vitamin has an effect on insulin resistance, inflammation, cholesterol levels and obesity. It is also thought to be connected to fertility, but there have been few human studies examining this issue. It is unclear whether vitamin D levels impact on pregnancy outcomes in women undergoing fertility treatment. 

This six month study included 540 patients with PCOS who were undergoing treatment to get pregnant. All women were taking part in a different study in which blood samples were taken. Vitamin D levels were measured.

Women with higher vitamin D levels had more ovulations compared to women with lower levels. 19% of the participants had a live birth. The likelihood of a live birth increased fourfold in women with vitamin D levels greater than 45 ng/ml. The likelihood of a live birth decreased by 44% in women with levels lower than 30 ng/ml. Each 1 ng/ml increase in vitamin D levels increased the likelihood of live birth by 2%.

Along with vitamin D deficiency (less than 30 ng/ml), age, higher body mass index (a measure of body fat), smoking, and hormone levels reduced the odds of having a baby. Racial differences in vitamin D levels were noted, with levels highest in white women and lowest in black women. 

Higher vitamin D levels also reduced the likelihood of pregnancy loss. There were no pregnancy losses in women with vitamin D levels greater than 39 ng/ml.

The study concluded that low levels of vitamin D may worsen ovulation problems in women with PCOS, whereas high levels of vitamin D may improve pregnancy outcomes.