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The Ultimate Prenatal Vitamin Guide

Before and during pregnancy, vitamins can help support a healthy mom and baby. Find out more on the benefits of prenatal vitamins and when and how to take them.

The Ultimate Prenatal Vitamin Guide

Getting adequate nutrition while pregnant is important to provide an optimal environment for the healthy growth and development of the baby. However, eating an adequate diet can be difficult during pregnancy due to morning sickness, cravings, food aversions, increased heartburn, or constipation.

Taking a prenatal vitamin is not a substitute for eating a nutritious and healthy diet. Instead, it can act as a supplemental way to provide adequate nutrition to mother and baby throughout pregnancy. 

Use this prenatal vitamin guide as a resource for what, how, and when to take prenatal vitamins during pregnancy.

What Are Prenatal Vitamins?

Prenatal vitamins are simply multivitamins formulated to meet the specific demands of the mother and growing baby during pregnancy. 

Getting adequate amounts of all essential nutrients is important during pregnancy, but prenatal vitamins can vary from other multivitamins. This is due to higher amounts of the following vitamins and minerals needed during pregnancy.

Folic Acid (Folate)

Folic acid is considered the supplemental form of the B vitamin folate and is needed to make new cells. Since the demand for making new cells increases dramatically during pregnancy, the need for adequate folic acid increases. 

Not getting adequate folic acid or folate during pregnancy increases the risk for birth defects. On the other hand, getting enough helps reduce the risk of and prevent neural tube defects.

The CDC suggests all women in reproductive years take 400 micrograms (mcg) of folic acid in addition to consuming a varied, balanced diet. Prenatal vitamins specifically have folic acid in them to match the higher demands of this nutrient during pregnancy. 

Fortified foods like breads, cereals or other grains provide folic acid. Leafy greens, vegetables, and legumes are also natural sources of folate.


Besides folic acid, another major nutrient with increased demand during pregnancy is iron. This mineral is needed to form new red blood cells and deliver oxygen to cells in the body. The need for this goes up during pregnancy for both the mother and growing baby. 

A benefit of prenatal vitamins is they provide more iron compared to other multivitamins. They are designed to help provide an extra source of iron and protect against and prevent iron deficiency anemia.

Calcium and Vitamin D

Calcium and vitamin D are needed for baby’s developing bones and teeth. As with iron, the need for calcium increases during pregnancy. 

The Recommended Dietary Allowance (RDA) for calcium for adults aged 19 to 50 years old is 1,000 mg per day. During pregnancy, the RDA increases to 1,300 mg per day.

Omega-3 Fatty Acids

Omega-3 fatty acids are needed for proper fetal neural and brain development during pregnancy. The exact amount of recommended intake of omega 3 fatty acid is not established but is likely higher during pregnancy. 

According to a review on omega 3 supplementation during pregnancy, most pregnant women likely do not get adequate omega-3 intake from diet alone. Therefore, most prenatal supplements also contain omega-3 as docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA).


Pregnant women have an increased need for iodine due to increased thyroid hormone production during pregnancy and transferring iodine to the fetus. Even mild iodine deficiency during pregnancy may increase the risk for lower cognitive function in children. Therefore, it is important to get adequate iodine during pregnancy. 

Most, but not all, prenatal supplements provide iodine. Check labels of prenatal supplements if getting iodine is a priority for your pregnancy. 

Food sources of iodine include most fish, seafood, dairy products, and iodized salt.

When Do I Need to Start Taking Prenatal Vitamins?

Dr. Jonathan Schaffir from The Ohio State University Wexner Medical Center suggests taking a prenatal vitamin as soon as pregnancy is suspected or confirmed. 

In fact, it is recommended for women in reproductive years to take a prenatal or multivitamin with folic acid before getting pregnant. This is because neural tubes of the fetus start developing in the first month of pregnancy, and this may be before a woman realizes she is pregnant.

Taking a prenatal vitamin is recommended for all pregnant women. It is a good idea to consult with a healthcare team with specific questions.

Do Vitamins for Pregnancy Have Side Effects?

Prenatal vitamins are considered safe and provide no side effects for most women. However, pregnant women with severe nausea or morning sickness may find it difficult to take a prenatal. Some women may also find the iron in prenatal multivitamins may increase constipation or nausea. 

Consult your doctor for any side effects you suspect are from a prenatal vitamin. The formulas can vary, and a healthcare provider can help offer other solutions for the best fit prenatal formula for personal needs.

Also do not take more than the recommended dose for prenatal supplements. If already taking vitamin supplements, consult a doctor or dietitian for guidance on taking any additional supplements.

How Do I Choose Prenatal Vitamins?

Many doctors or midwife practices provide a prescription for a prenatal multivitamin. They provide the recommended levels of nutrients, as well as a supplemental omega-3 fatty acid. 

However, there are also many prenatal supplements available over the counter. Some prenatal supplements are offered in a chewable form, which may benefit some women overtaking prenatal supplements in pill form.

In general, most prenatal supplements offer the recommended nutrient levels needed during pregnancy. However, if you have specific nutrient or health concerns, follow the recommendation of a healthcare team for which prenatal multivitamin would work best.

Recommended Prenatal Vitamins

Consult a healthcare team for best individual recommendations for prenatal multivitamins. Bring up any specific questions with them for any individual nutrients of concern. 

If taking a prenatal vitamin before becoming pregnant, as suggested, the most important aspect for this time frame is getting adequate folic acid supplementation. All prenatal vitamin supplements should provide. 

If you notice any potential side effects with taking prenatal multivitamins, discuss best resolutions or alternatives with the professionals.