The ABCs of vitamins in pregnancy

From A to K, vitamins play a critical role in a healthy pregnancy

The ABCs of vitamins in pregnancy

Prenatal vitamins are important to good nutrition during pregnancy. They promote proper development of the growing baby and the health of the mother. When taken in proper amounts, vitamins are beneficial. However, taken in excess, vitamins can be harmful.

It’s important to know what extra vitamin supplements — if any — are needed during pregnancy.

Your doctor can help you decide: Find a primary care provider at Sanford Health

Most nutritional advise for pregnant women is based on reports from the Institute of Medicine and the U.S. Department of Health and Human Services. Recommended dietary allowances (RDA) are levels of vitamins and nutrients recommended by expert panels based on extensive scientific evidence.

Multivitamin supplements are recommended for pregnant women who do not consume an adequate diet. Groups at increased risk for vitamin and nutrient deficiencies include:

  • Women with multiple gestations
  • Heavy smokers
  • Vegetarians
  • Women with a history of bariatric surgery
  • Substance abusers
  • Women with Crohn disease or bowel resection
  • Adolescents
  • Women with lactase deficiency

These women should have a consultation with a dietitian at the beginning of pregnancy to determine the proper diet and necessary vitamin supplements.

Amounts of prenatal vitamins

The amount of vitamin in each prenatal pill or multi-vitamin supplement can vary depending on the product used, making it important to check your vitamins and not exceed the upper safe limits of daily intake.

The following is a list of the recommended dietary allowance and tolerable upper limits for pregnant women:

Vitamin A

Coming in forms that include retinal, retinyl esters, retinol and retinoic acid — the most common, Vitamin A is required for:

  • Cell growth
  • Genes
  • Development of the vertebrae, spinal cord, limbs, heart, eyes and ears

Because the foods Americans eat contain sufficient amounts, vitamin A deficiency is rare in the United States. Women of lower socioeconomic status should consume more foods with vitamin A rather than use vitamin A supplements.

The daily requirement of vitamin A is 770 micrograms.

Some over-the-counter multivitamins can contain too much vitamin A, so it is important to check the amount and make sure you are not taking more than 3,000 micrograms of vitamin A daily. Taking too much vitamin A has been linked to birth defects of the baby involving the head, face and heart.

Vitamin D

Vitamin D is important for the health of your bones and the absorption of calcium. During pregnancy, vitamin D is also important for the growth of your baby and low vitamin D during pregnancy can result in a small baby, preterm birth and bone fractures.

Women who should take extra vitamin D during pregnancy include those who:

  • Are strict vegetarians
  • Have limited exposure to sunlight
  • Avoid dairy foods

You can have your vitamin D level checked at the beginning of a pregnancy by asking for a 25-hydroxy-D level from your doctor. The recommended dose during pregnancy is 600 international unites (IU) and most prenatal vitamins contain 400 IU of vitamin D. However, some contain as little as 200 IU or as much as 1,000 to 1,2000 IU.

There are different forms of vitamin D in multivitamin supplements and prenatal vitamins — check to see what type of vitamin D your multivitamins contain. Many non-prescription vitamins labeled vitamin D contain ergocalciferol (vitamin D2) rather than cholecalciferol (vitamin D3). Vitamin D3 is better absorbed into your body and more effective at increasing your vitamin D level.

Taking as much as 1,000 to 4,000 IU per day of vitamin D is safe during pregnancy. However, unless your diet is deficient in vitamin D and your 25-hydroxy-D level is low, studies have shown no proof that taking extra vitamin D routinely during pregnancy helps lower preeclampsia, preterm birth or low birth weight.

Vitamin C

An antioxidant that functions to keep you healthy, vitamin C also helps you absorb iron. Women who smoke should take extra vitamin C in their diet. Pregnant women should take 85 mg per day.

There is no evidence that taking extra amounts of vitamin C helps prevent preeclampsia, stillbirth, preterm birth or low birth weight.

Vitamin E

There is no need to take extra vitamin E during pregnancy, as studies have shown no benefit in lowering stillbirth, preterm birth, preeclampsia or low birth weight.

Some studies have reported patients having more abdominal pain and premature rupture of membranes at term when taking vitamin E supplements during pregnancy. Taking too much vitamin E can cause platelet and bleeding problems.

Vitamin B6

Vitamin B6 is important in your metabolism and in the formation of red blood cells. Taking extra vitamin B6 during pregnancy helps relieve nausea and vomiting associated with morning sickness.

It is uncommon to find a deficiency in Vitamin B.

Vitamin B12

Vitamin B12 is responsible for fat and carbohydrate metabolism and protein synthesis. Poor diets and strict vegetarian diets can cause deficiency, resulting in anemia and neurologic abnormalities.

Vitamin K

Vitamin K is important in helping blood clot. Though extra vitamin K is not needed during pregnancy, women who are pregnant and using anti-seizure medications are at increased risk of vitamin K deficiency in their baby. These women should take oral vitamin K, at a rate of 10 mg daily, from 36 weeks until delivery.


Taking an adequate amount of folate is important to help your baby from having the birth defect spina bifida. Folate is a vitamin important in making the body’s DNA and RNA.

Folate deficiency is the most common vitamin deficiency in pregnancy, with low folate levels caused by poor diet and genetic factors.
You should be taking an adequate level of folate one month prior to conception and continue through at least the first trimester.
Good sources of folate in your diet include:

  • Fruits
  • Green vegetables
  • Beans
  • Nuts
  • Bread

Folate requirements are increased in pregnancy with the recommendation that women take 400 to 800 micrograms (0.4 to 0.8 mg) of folate prior to becoming pregnant and continue throughout pregnancy.

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Posted In Health Information, Nutrition, Pregnancy, Women's