8 things you need to know about Vitamin D and Pregnancy


1. Vitamin D is more accurately described as a hormone, not a vitamin. It is produced by the skin upon sun exposure, and regulates bone metabolism (keeping bones strong and healthy), strengthens the immune system, fights inflammation, and supports healthy glucose metabolism.

2. More than 40% of Americans are Vitamin D deficient. Individuals with low vitamin D are at an elevated risk of cancer, heart disease and diabetes.

3. Certain factors increase the likelihood of Vitamin D deficiency significantly:
Being an ethnic minority, especially with darker skin
Wearing sunscreen or otherwise having limited sun exposure, including living in a cold climate or northern latitude
Being vegetarian
Having a BMI over 30

4. You can be deficient in Vitamin D without having any symptoms. To determine if you are deficient, you can have a lab test done to check if your blood levels of vitamin D are in the normal range, which is above 32ng/mL (or above 75nmol/L).

5. Complications associated with inadequate Vitamin D during pregnancy include elevated risk of pre-term birth, cesarean delivery, preeclamsia, infection, and gestational diabetes. Further, a newborn’s vitamin D status is highly dependent on mom’s status, so infants born to mom’s with D deficiency are at an increased risk of abnormal bone growth, fracture and rickets.

6. It’s hard to get enough vitamin D through your diet. Some people recommend increasing sun exposure to increase blood levels of vitamin D, but there are concerns with elevated risk of skin cancer through this route. Vitamin D supplements effectively increase serum Vitamin D without skin cancer risk.

7. There is currently no universal recommendations for taking Vitamin D supplements in pregnancy. Most prenatal vitamins contain about 400 IU of vitamin D. A 2010 study found that pregnant women taking 4000 IU of Vitamin D per day cut their risk of pregnancy complications in half compared to women taking only the 400 IU in their prenatal vitamin. The American Congress of Obstetricians and Gynecologists takes a conservative approach and recommends supplements of 1000 to 2000 IU daily for pregnant women who are Vitamin D deficient. Their opinion statement does say “most experts agree that supplemental vitamin D is safe in dosages up to 4,000 international units per day during pregnancy or lactation.”

8. Vitamin D supplementation can be beneficial during lactation as well. Research indicates that having lactating moms take 2000 IU of Vitamin D per day works as well at protecting infant Vitamin D status (through higher levels of vitamin D in the breast milk) as directly supplementing the baby with 400 IU vitamin D.

Talk to your Nurse Midwife or Obstetrician about your risks for vitamin D deficiency and make a plan together about any supplements to take. Preventing or treating vitamin D deficiency will protect both your and your baby’s health.

Lindsay Pasdera, MS RDN

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