Prenatal Vitamins

Reviewed by Traci C. Johnson, MD on November 12, 2022

What Are Prenatal Vitamins?

Prenatal vitamins are supplements made for pregnant women to give their bodies the vitamins and minerals needed for a healthy pregnancy. Your doctor may suggest that you take them when you begin to plan for pregnancy, as well as while you’re pregnant.

Eating a healthy diet is always a wise idea -- especially during pregnancy. It's also a good idea to take a prenatal vitamin to help cover any nutritional gaps in your diet.

What to Look for in Prenatal Vitamins

Prenatal vitamins help ensure that you get the nutrients you need for a healthy pregnancy.

Look for prenatal vitamins that have:

400 micrograms (mcg) of folic acid
400 IU of vitamin D
200 to 300 milligrams (mg) of calcium
70 mg of vitamin C
3 mg of thiamine
2 mg of riboflavin
20 mg of niacin
6 mcg of vitamin B12
10 mg of vitamin E
15 mg of zinc
17 mg of iron
150 micrograms of iodine

In some cases, your doctor will give you a prescription for a certain type of prenatal vitamin.

Folic Acid, Calcium, Iodine, and Iron

Folic acid

If getting pregnant is a possibility for you, you should take folic acid. It can prevent birth defects that affect the baby’s brain and spinal cord. Neural tube defects develop early in pregnancy, before many women know they’re pregnant; half of all pregnancies are unplanned. This is why doctors recommend that any woman who could get pregnant take 400 micrograms (mcg) of folic acid daily, starting before conception and continuing for the first 12 weeks of pregnancy.

If you’ve had a baby with a neural tube defect you should talk with your health care provider about folic acid. Studies have shown that taking a larger dose (up to 4,000 micrograms) at least one month before and during the first trimester may help if you’ve had a baby with this defect. But talk to your doctor about what’s right for you.

Foods that have folic acid include:

Green leafy vegetables
Nuts
Beans
Citrus fruits
Many other foods fortified with folic acid

Even though you can get folic acid from food, it's a good idea to take a supplement as a backup.

Calcium

Calcium is also important for a pregnant woman. It can help prevent you from losing your bone density as the baby uses calcium for its own bone growth.

Iodine

Iodine is critical for a woman’s healthy thyroid function during pregnancy. Iodine deficiency can cause:

Miscarriage
Stillbirth
Stunted physical growth
Severe mental disability
Deafness

Iron

Iron helps your body make more blood red cells. These blood cells carry oxygen to the baby that it needs to develop.

What About Other Nutrients?

There are other nutrients that may improve the health of your pregnancy. Your doctor can help you decide if you need to take supplements that include:

Omega-3 fatty acids: These fats, which include DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), come only from food sources such as fatty fish and nuts. Studies show omega-3s can lower your risk of preterm birth and of having a baby with low birth weight. If you don’t eat much food that’s rich in omega-3s, ask your health care provider if a supplement is right for you.

Choline: Although your body can make some choline on its own, you get most of it from food. Rich sources include beef, pork, chicken, fish, and eggs. Many pregnant women don’t get enough choline, which the baby needs for healthy brain growth.

When to Start Taking Prenatal Vitamins

The best time to start taking prenatal vitamins is before conception. Folic acid is especially important. You should begin taking a folic acid supplement at least 1 month before you try to get pregnant to prevent birth defects.

Some doctors recommend that all women who could have a baby take prenatal vitamins, even if they don’t plan a pregnancy.