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Prenatal vitamins are used to help meet nutritional needs of people, especially those who may be pregnant or breastfeeding. Common side effects from prenatal vitamins can include loss of appetite, nausea, diarrhea, or constipation. Serious side effects are rare. Before taking a prenatal vitamin, tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

Uses

What are prenatal vitamins used for?

Prenatal vitamins are commonly used to help meet nutritional needs of certain people, especially if they are pregnant, trying to get pregnant, or breastfeeding or if they have recently had a baby.

Prenatal vitamins may also be used for other conditions as determined by your health care provider.

How do prenatal vitamins work (mechanism of action)?

Prenatal vitamins work to provide you with vitamins and minerals if you do not get enough of them in the things that you eat and drink. The active ingredients in prenatal vitamins can vary based on the specific product, but they usually include folic acid, iron, other vitamins and minerals, and possibly other ingredients, such as omega-3 fatty acids. Always check the label to see what ingredients your product has. Your body uses these vitamins and minerals for many different functions, including growth, energy, and staying healthy.

How are prenatal vitamins supplied (dosage forms)?

Prenatal vitamins are available as a supplement in various forms and strengths, including an oral capsule, liquid, soft gel, and tablet.

How should I store prenatal vitamins?

Most prenatal vitamins should be stored at room temperature, usually between 68 F and 77 F (20 C and 25 C). Follow the storage instructions for the product you are using. Avoid exposing prenatal vitamins to extreme heat, such as temperatures at or above 104 F (40 C). Protect prenatal vitamins from light and moisture. If your prenatal vitamins come in a blister pack, do not remove them from the blister pack until you are ready to take one. If you are not sure how to store your prenatal vitamins, ask your pharmacist. 

Side Effects

What are the most common side effects of prenatal vitamins?

The most common side effects of prenatal vitamins are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Loss of appetite
  • Nausea, diarrhea, or constipation

There may be other side effects of prenatal vitamins that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of prenatal vitamins?

While less common, the most serious side effects of prenatal vitamins are described below, along with what to do if they happen.

Severe Allergic Reactions. Prenatal vitamins may cause allergic reactions, which can be serious. Stop taking prenatal vitamins and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Warnings & Precautions

Who should not use prenatal vitamins?

Allergies to Ingredients. People who are allergic to any of the following should not take prenatal vitamins.

  • Minerals
  • Prenatal vitamins
  • Vitamins
  • Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific prenatal vitamin products they stock.

What should I know about prenatal vitamins before using them?

If prenatal vitamins were prescribed to you by a health care provider, use them as prescribed. If you are using an over-the-counter prenatal vitamin, follow the instructions that come with the product. Do not take more prenatal vitamins than is recommended. 

Do not share prenatal vitamins that were prescribed to you by a health care provider with other people, even if they have the same condition as you. It may harm them.

Prenatal vitamins usually have iron in them. Accidental iron overdoses can lead to death, especially in children younger than 6 years. Keep prenatal vitamins out of the reach of children.

If you are taking a liquid prenatal vitamin, follow any instructions on the label about shaking the liquid before measuring your dose. Shaking it before measuring helps to make sure you get the right amount. Use an accurate measuring device to measure your dose. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Ask your pharmacist what measuring device to use.

Prenatal vitamins may affect the results of certain lab tests. Tell all of your health care providers, especially those ordering lab tests, that you are taking a prenatal vitamin. 

What should I tell my health care provider before using prenatal vitamins?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if prenatal vitamins are right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Before taking a prenatal vitamin, tell your health care provider if you have any of the following.

Other Medicines and Supplements. Prenatal vitamins may interact with other medicines and supplements. Before taking prenatal vitamins, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. Tell your health care provider if you are pregnant or plan to become pregnant. 

Breastfeeding. Tell your health care provider if you are breastfeeding or plan to breastfeed.

Interactions

Do prenatal vitamins interact with foods or drinks?

Your body will likely absorb prenatal vitamins better if you take them without food or even at bedtime. You can take them with food to help relieve any stomach-related side effects. 

It is unknown if drinking alcohol will affect prenatal vitamins. But drinking alcohol while you are pregnant or breastfeeding may expose your child to alcohol. 

Do prenatal vitamins interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking prenatal vitamins.

  • Levodopa, which is a medicine for Parkinson’s disease
  • A blood thinner, which is a medicine used to treat or prevent blood clots
  • Aspirin, which is in many prescription and OTC products, including those for pain, swelling, and fever
  • An antiplatelet medicine, such as aspirin/dipyridamole, cilostazol, clopidogrel (Plavix), or ticagrelor (Brilinta), which is a medicine used to prevent blood clots
  • Any other multivitamin 
  • Any other vitamin or supplement that has vitamin A in it

This may not be a complete list of medicines that can interact with prenatal vitamins. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too many prenatal vitamins?

If you or someone else has used too many prenatal vitamins, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of prenatal vitamins?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.