Preterm labor

Preterm labor is labor that starts before 37 completed weeks of pregnancy. Your baby can have serious health problems if born too early.

Learn more about preterm labor from Allina pregnancy care.

Vitamin D

Vitamin D is a fat-soluble vitamin. It helps the body absorb calcium.

Learn more about vitamin D in our health library.

Taking vitamin D during pregnancy

Vitamin D

Vitamin D is important to keep your bones strong and healthy. It also helps your body fight off germs, and helps your nerves carry messages to and from your brain.

A 2010 study by the Pediatric Academic Societies suggests that vitamin D may help prevent preterm labor, preterm birth and infections.

Sources of vitamin D

You can get vitamin D from three sources: food, sun exposure and supplements (pills).

• Food - Very few foods naturally have vitamin D. The best sources are fatty fish (like salmon or tuna). Nearly all milk has added vitamin D. Some brands of cereal, orange juice and margarine also have added vitamin D.
• Sun exposure - Your body makes vitamin D when your skin is exposed to direct sunlight. This is why vitamin D is known as the "sunshine vitamin." Cloud cover, shade and using sunscreen or clothing to protect your skin from the sun will cut down the amount of vitamin D your skin makes. (Sunlight filtered through a window will not help your body make vitamin D.) In the northern half of the United States during the winter, energy from the sun is not enough for people to make vitamin D.
• Supplements - The easiest way to get vitamin D is through supplements (vitamins).

Vitamin D deficiency

Not getting enough vitamin D puts you at risk for weak bones, bone pain and muscle weakness.

Research is ongoing to study links between low levels of vitamin D and type 1 diabetes, heart disease, depression, certain cancers, high blood pressure during pregnancy, and low birth weight, among other conditions.

Vitamin D blood test

Your blood will be tested for your vitamin D level during your prenatal blood draw.

If your blood test shows that your vitamin D level is too low, your health care provider may want you to take:

• an over-the-counter supplement. There are different strengths. Your health care provider will tell you what strength is right for you.
• a prescription supplement. The prescription strength is much stronger than the over-the-counter strengths. Follow your health care provider's instructions. Taking too much vitamin D can cause serious problems.

Follow-up blood tests

Your vitamin D levels will need to be checked every eight weeks, as needed.

If your level is still low, your health care provider may change how much vitamin D you need.

If you have questions or concerns, please talk with your health care provider.