Vitamin D in Pregnancy & Fertility

Vitamin D plays an important role in pretty much all the systems in our bodies from the immune and nervous systems to the reproductive and cardiovascular systems.

And vitamin D deficiency is associated with all kinds of health conditions, especially when we look at chronic health conditions.

From a reproductive standpoint, vitamin D deficiency is associated with endometriosis, PMS, period pain (dysmenorrhea), PCOS, and unexplained infertility. It is also associated with pregnancy outcomes such as pregnancy loss, gestational diabetes, pre-eclampsia, low birth weight, and more.

Supplementing vitamin D becomes really important when we are vitamin D deficient because we see lower risks of all of those outcomes in pregnant people who are replete in this crucial vitamin. Vitamin D is involved in our hormonal processes, endometrial receptivity, and immune function — all of which are crucial when it comes to fertility and pregnancy.



4 green sperm clipart surrounding a pink egg (light pink circle with a magenta border)
Clipart sun (yellow hollow circle with rays around it) with the words vitamin D in the centre
2 clipart test tubes (one pink and one green) with blood in them

Testing is easy – it’s a simple blood test – and is recommended to understand what your current vitamin D status is so that the appropriate supplementation can be determined. In Canada, it’s common for people to take vitamin D, especially in the winter, but if you’re super deficient, then low-dose vitamin D (for e.g. 1000IU) may not be enough. And if you’re taking mega doses then we risk vitamin D toxicity. Talk to your doctor about testing — they might not think it’s necessary since most Canadians are deficient, but if you’re super deficient a low-dose supplement might not be enough to bring your levels up to a sufficient one. If you’re in Ontario, Canada, vitamin D testing is not covered under OHIP (except for special cases) but it’s worth the ~$40.