What to know about prenatal vitamins

A pregnant woman holding prenatal vitamins

Between morning sickness, fleeting cravings and random aversions, getting good nutrition during pregnancy can be rough. Even if you’re eating a balanced diet, it’s still possible to miss some essential nutrients.

Enter prenatal vitamins.

They’re an easy way to fill in any gaps and support both your body and your baby’s growth and development. Here’s what you need to know about them when you’re pregnant.

What are prenatal vitamins?

Pregnancy leads to increased nutritional demands, both because of the needs of the developing baby and the changes the body goes through to accommodate the pregnancy. While sufficient nutrition largely comes through a well-balanced diet, it’s helpful to take a multivitamin to make sure that all the nutritional requirements of the pregnancy are met.

Why it’s important to take prenatal vitamins

Prenatal vitamins have higher amounts of certain nutrients, namely folic acid and iron, and may also contain essential fatty acids (DHA). For certain vitamins and supplements, there are specific benefits.

Some examples:

  • Folic acid helps prevent certain birth defects (like spina bifida) in babies.
  • Iron helps prevent anemia (low blood count), which may lead to fatigue and fainting, during pregnancy.
  • DHA (a type of polyunsaturated fatty acid) may improve fetal neural development and fetal growth when taken in the third trimester.
  • Extra calcium is good for bone strength.
  • Vitamin B6 may be useful for suppressing nausea in pregnancy.

What’s in prenatal vitamins: Key nutrients to look for

Although prenatal vitamins typically contain the full range of vitamins and minerals, the most important are folic acid, B vitamins, calcium and iron. Calcium and iron are particularly important because the requirements for these minerals are higher during pregnancy.

However, these are the ingredients most often left out of gummy vitamins, which can be popular because of taste and ease of use. If you choose the gummy, you may need to take extra iron or calcium if they have been left out.

When to start and stop taking prenatal vitamins

Start using a multivitamin that contains folic acid whenever you think you might conceive. Because the kind of birth defects that arise from a lack of folic acid start to form before many people even realize they’re pregnant, it’s important to supplement this nutrient even before conception.

Other nutrient demands increase only after pregnancy starts, so you don’t have to use a “prenatal vitamin” until after the pregnancy test is positive. If you’re unable to tolerate the vitamin because you feel sick in the first trimester, it’s OK to start once you’re feeling better.

You should continue to take a prenatal vitamin for the duration of breastfeeding, however long that may be. This is because lactation (making breast milk) also increases nutritional demands, especially of calcium and iron.

Expert Guide to a Healthy Pregnancy: Answers to more of your questions

Prenatal vitamins and side effects

The ingredient that’s most likely to cause gastrointestinal side effects is iron, which may lead to indigestion and constipation. There are different iron preparations available, so those who experience these effects with one vitamin may want to try a different vitamin with a slower-release form of iron.

Other ingredients don’t necessarily have side effects, but they may be harmful if too much is ingested. Too much vitamin A can have harmful effects on the fetus, but it’s fine when taken as beta-carotene, a safe, plant-based precursor. Too much iodine and fat-soluble vitamins (D, E and K) may also be harmful.

Finally, prenatal vitamins that pack in all these nutrients may be big — they may be hard for some people to swallow and cause gagging. Using a chewable alternative may be an option.

This advice applies to most low-risk people and pregnancies. There are certain situations (those who have had gastric bypass surgery, with eating disorders or carrying twins and triplets), in which nutritional needs are different. In those cases, contact your prenatal care provider about the best nutritional supplement regimen.

Is it OK to take a prenatal vitamin if I’m not pregnant?

There is no harm to using a prenatal vitamin if not pregnant, but it’s more than necessary for most people.

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