You may not need a separate vitamin D pill. The recommended amount is 600 IU a day, and many prenatal vitamins include some vitamin D. A separate supplement makes sense when your prenatal, food, and sun exposure don’t add up, or when a blood test shows you’re low.

The short version

  • The target: 600 IU (15 micrograms) a day during pregnancy and breastfeeding, according to MedlinePlus.
  • Start with your prenatal: check how much vitamin D it contains, then add what you get from fortified milk, cereal, and fish.
  • D3 or D2: both raise vitamin D in your blood, but D3 might raise it higher and for longer, according to the NIH.
  • Take it with food: vitamin D is absorbed best with a meal.
  • Stay under 4,000 IU a day from all sources unless your provider prescribes more to treat a deficiency.

Do you need more than your prenatal?

Add up a typical day:

Source Vitamin D
Your prenatal vitamin Check the label; amounts vary
1 cup fortified milk About 100 IU
Fortified cereal, orange juice, or yogurt Check the Nutrition Facts label
Salmon or other fatty fish One of the best food sources

Milk value from MedlinePlus, based on 400 IU per quart.

If that adds up to around 600 IU, you’re likely covered. For example, a prenatal with 400 IU plus 2 cups of fortified milk (about 200 IU) reaches 600 IU. ACOG’s 2011 committee opinion on vitamin D said that women who aren’t at higher risk for low vitamin D generally get enough from a prenatal vitamin. A separate supplement is worth discussing with your doctor or midwife if:

  • Your prenatal has little or no vitamin D, and you don’t drink fortified milk or eat fortified foods.
  • You get little sun, for example because you live farther north, it’s winter, you cover most of your skin, or you use sunscreen whenever you’re outside (which is a good habit).
  • You have darker skin, which makes less vitamin D from the same amount of sun, according to MedlinePlus.
  • You have obesity or have had gastric bypass surgery. People in these groups may need more vitamin D than others, according to the NIH.
  • A blood test showed your vitamin D is low. See Vitamin D Deficiency in Pregnancy.

Reading the label

D3 or D2. Supplements and fortified foods use one of two forms: D3 (cholecalciferol) or D2 (ergocalciferol). Both raise the amount of vitamin D in your blood, but D3 might raise it higher and keep it up longer, according to the NIH. If you’re vegan, check the label or ask the maker whether the vitamin D comes from an animal or plant source.

IU or mcg. Labels list vitamin D in international units (IU), micrograms (mcg), or both. One microgram equals 40 IU, so:

Micrograms (mcg) International units (IU)
10 mcg 400 IU
15 mcg 600 IU (daily need in pregnancy)
25 mcg 1,000 IU
50 mcg 2,000 IU
100 mcg 4,000 IU (upper limit)

Take it with a meal. Vitamin D supplements are absorbed best when taken with food, according to the NIH.

Look for independent testing. A seal from U.S. Pharmacopeia (USP), NSF, or ConsumerLab means the product was checked to contain what the label says.

Add it all up. Count your prenatal, any separate vitamin D, and any calcium-plus-D product together. It’s easy to double up without noticing.

Safety

The upper limit is 4,000 IU (100 mcg) a day for teens and adults, including during pregnancy and breastfeeding, from food and supplements combined, according to MedlinePlus.

Too much is almost always from supplements. Very high intakes make your body absorb too much calcium. High blood calcium can cause nausea, vomiting, constipation, poor appetite, weakness, confusion, and kidney stones, and can damage the kidneys over time. Sunlight and food don’t cause this.

Higher doses are sometimes prescribed. If a blood test shows your vitamin D is low, or you have a condition that makes it harder to absorb, your provider may recommend a higher dose for a while. Take that amount as directed, and ask when your level will be rechecked.

Tell your provider about your medicines. Some medicines can affect how your body uses vitamin D, so bring a list of everything you take, including supplements, to your appointment.

More isn’t better. Research reviews have found that taking 4,000 IU or more a day in pregnancy made little or no difference to preeclampsia, gestational diabetes, preterm birth, or low birth weight compared with lower doses, according to Cochrane.

What to do now

  • Check your prenatal’s Supplement Facts panel for vitamin D, in IU or mcg.
  • Add up a typical day using the table above.
  • If you’re well short of 600 IU, ask your provider whether a separate supplement or a blood test makes sense.
  • Keep the total under 4,000 IU unless your provider prescribes more.

Related reading

Sources

Updated November 2026. This article is for general information and is not a substitute for advice from your health care provider.