A new CMAJ Open study has revealed that in vitro fertilization (IVF) is more successful among women who have sufficient levels of vitamin D.

The researchers found that women with sufficient levels of vitamin D were more likely to have a successful clinical pregnancy compared to those with insufficient levels.

Vitamin D is produced by the body from exposure to sunlight, it is important for proper calcium metabolism and is vital for strong, healthy bones.

Vitamin D deficiency is a common problem among women in the U.S., particularly during the winter months.

A total of 173 women participated in the study, conducted at Mount Sinai Hospital in Toronto, Ontario. Over half (55%) of them reported low levels of vitamin D.

Overweight women were at a higher risk of vitamin D deficiency, especially those with body mass indexes (BMIs) greater than 40.

A study published in a recent issue of PLoS Medicine, found clear evidence that obesity can cause vitamin D deficiency.

What is Vitamin D deficiency? UCSD School of Medicine explanation:



The pregnancy rates per cycle start were higher among women with sufficient levels of vitamin D than those with very low levels (52.7% vs 34.7% respectively).

The researchers defined clinical pregnancy as “the visibility of an intrauterine sac with ultrasound.”

Schneelandschaft Vorarelberg Furx
During the winter many women suffer from vitamin D deficiency due to lack of sunlight.
Dr. Kimberley Garbedian, Department of Obstetrics and Gynecology, Mount Sinai Hospital, Toronto, Ontario, said “the serum level of 25(OH)D, as a marker of vitamin D level, may be a predictor of IVF pregnancy among women undergoing treatment for infertility.”

He added that the participants in the study with sufficient vitamin D levels had “significantly higher rates of clinical pregnancy following IVF compared with women with insufficient or deficient levels.”

The finding has significant therapeutic implications, considering that over half of the women in the study had insufficient levels.

The team suggests that health professionals should monitor vitamin D levels during infertility treatmen and provide supplements if necessary.

Dr. Kimberly Liu, a fertility specialist at Mount Sinai Hospital’s Centre for Fertility and Reproductive Health, concluded:

“We know that Canadians are prone to vitamin D insufficiency, especially during the winter months and this study suggests that vitamin D supplementation could provide an easy and cost-effective means for improving pregnancy rates.

At our centre, we are always looking at ways to improve a patient’s success with fertility treatments; this study gives us an opportunity for further research so we can continue to help our patients.”

The authors of the study said that an easy and cost effective way of addressing this issue is through adequate vitamin D supplementation.

In addition, a study published in the journal Neurology found that high levels of Vitamin D in the blood could prevent multiple sclerosis (MS) in mothers.

Written by Joseph Nordqvist