Supplements · 5 min read · Due Team

Vitamin D and Fertility: Why It Matters More Than Most People Think

Vitamin D deficiency is common and directly relevant to both fertility and early pregnancy. Here's what the research shows and what to do about it.

Vitamin D is one of the few supplements where deficiency is both widespread and clearly connected to reproductive outcomes. Getting your levels checked is one of the most useful things you can do early in your fertility journey.

How vitamin D affects fertility

Vitamin D receptors are present in ovarian tissue, the uterine lining, and the placenta. Research has linked adequate vitamin D levels to better IVF outcomes, improved implantation rates, and lower risk of miscarriage. It also plays a role in immune regulation — relevant because early pregnancy requires the immune system to tolerate the embryo.

How common is deficiency

Studies consistently find that 40 to 50 percent of reproductive-age women are vitamin D deficient or insufficient. People with darker skin, limited sun exposure, higher BMI, or who live at northern latitudes are at higher risk.

What levels to aim for

Most fertility specialists recommend vitamin D levels of 40 to 60 ng/mL. Standard "normal" lab ranges often go as low as 20 ng/mL, which many reproductive endocrinologists consider insufficient. Ask for your actual number, not just whether you're "in range."

How much to supplement

A common starting point is 2,000 to 4,000 IU per day of vitamin D3. Recheck levels after 8 to 12 weeks of supplementation.

The bottom line

Vitamin D deficiency is common, easy to identify, and directly relevant to fertility and pregnancy. Get your levels tested and supplement accordingly.

Want personalized guidance?

Chat with Due for a breakdown based on your specific situation.

Chat with Due

Want personalized guidance? Chat with Due for a breakdown based on your specific situation.