Vitamin D deficiency linked to recurrent pregnancy loss, says new study

A new study in the American Journal of Reproductive Immunology suggests a lack of the vitamin could prevent a mother's immune system from adapting to the baby.

Sunshine vitamin may play role in calming immune response to pregnancy

A new study suggests that vitamin D is an important regulator of the body's immune response to pregnancy. (Ian Waldie/Getty Images)

Vitamin D — the sunshine vitamin — can be in short supply among sun-starved Canadians, and a new study says there may be a relationship between vitamin D deficiency and pregnancy loss. 

The study, published in the American Journal of Reproductive Immunology, suggests that vitamin D may be an important regulator of the body's immune response to pregnancy.

The underlying cause in half of all cases of recurrent pregnancy loss — defined as two or more miscarriages or the spontaneous loss of three or more pregnancies before 24 weeks — is unknown, according to the study's authors.

But their review of seven recent studies on the subject has led them to believe that vitamin D may play a role in calming a mother's immune system. If this doesn't occur, it could attack the fetus and terminate the pregnancy. 

"Vitamin D has been shown to modulate the immune reaction in the fetomaternal [mother-fetus] interface and to contribute to the creation of a more favourable environment for pregnancy development, while deficiency has been associated with pregnancy loss," the authors conclude. 

People with darker skin, vegetarians, or those who get less exposure to sun are more likely to suffer from deficiency of the vitamin, the study adds.

Vitamin D in the North

That could especially be a problem in the North, where sunlight is lacking during the winter months. 

Nunavut's chief public health officer, for example, warned in 2010 that up to 90 per cent of Nunavummiut suffered from a lack of vitamin D. 

"We know here that diet alone is not sufficient," Dr. Geraldine Osborne told CBC News at the time, adding that traditional diets contain more vitamin D than modern ones.

"Older people tend to eat more country foods and younger people tend to eat more store-bought foods. So definitely, country foods are a wonderful source of vitamin D," Osborne said.

She cautioned, however, that vitamin D supplements may be necessary.

The recent study says that further research is needed to determine whether supplements should be considered for vitamin-deficient women who have experienced recurrent pregnancy loss.

Yukon also launched its own campaign to increase vitamin D intake in 2016. Its "We all need the D" campaign garnered some racy interpretations that set the Internet ablaze.

Lack of vitamin D can also lead to low bone density or even rickets, a debilitating bone disease.


To encourage thoughtful and respectful conversations, first and last names will appear with each submission to CBC/Radio-Canada's online communities (except in children and youth-oriented communities). Pseudonyms will no longer be permitted.

By submitting a comment, you accept that CBC has the right to reproduce and publish that comment in whole or in part, in any manner CBC chooses. Please note that CBC does not endorse the opinions expressed in comments. Comments on this story are moderated according to our Submission Guidelines. Comments are welcome while open. We reserve the right to close comments at any time.

Become a CBC Member

Join the conversation  Create account

Already have an account?