When and Why Should You Take Prenatal Vitamins?
Filmstax / Getty Images
Medically reviewed by Monique Rainford, MD
Prenatal vitamins are an important part of a healthy pregnancy and a fetus's development. They help support nutritional deficiencies and reduce the chances of certain congenital disabilities.
Prenatal vitamins are recommended during pregnancy, and experts encourage starting them before becoming pregnant, especially in the month leading up to pregnancy.
This article discusses the benefits of prenatal vitamins and how soon you should consider taking them if needed.
Filmstax / Getty Images
This article references sources that may specify a female-specific language about pregnancy and birth. These references do not reflect Verywell Health's brand guidelines on terminology related to sex and gender.
How Important Are Prenatal Vitamins?
Some key minerals and nutrients support a healthy pregnancy and a growing baby’s development in the womb. While pregnant, the levels of certain essential minerals can deplete.
When taken as directed, prenatal vitamins are a valuable tool in helping provide the correct amount of those nutrients daily. In addition, in some populations of women, prenatal vitamins have been shown to lower the risk of preterm labor and preterm birth, a low birth weight, certain congenital disabilities, preeclampsia (high blood pressure during pregnancy), and other health issues.
Risks of Not Taking Prenatal Vitamins
Insufficient vitamin intake may lead to an increased risk of certain health complications, including:
Preeclampsia
Low birth weight
Neural tube defects
Developmental delays
There is also some evidence that taking prenatal vitamins during pregnancy could help reduce the chances of developing postpartum depression 21 months postpartum.
Ingredients in Prenatal Vitamins
During pregnancy, there are certain minerals that the body needs to keep the pregnant person and baby healthy. There isn't a set standard for prenatal vitamin ingredients, but most contain vital nutrients like folic acid, iron, calcium, vitamin D, vitamin C, vitamin A, and omega-3 fatty acids (or DHA). There are also certain amounts that experts recommend for each vitamin.
When looking for the best prenatal brand, it's a good idea to consider whether the brand is trusted, the vitamins are third-party tested, and the ingredients meet your nutritional needs.
Here are some of the types of prenatal vitamins you might find over the counter:
With folic acid: Folic acid is a synthetic form of folate, also known as vitamin B9, and it helps promote the healthy development of the nervous system during pregnancy. Specifically, it reduces the risk of neural tube defects.
With iron: Iron is a mineral that helps with brain development. Without enough of it, anemia can develop. This can lead to preterm birth or low birth weight.
With DHA: DHA, or omega-3 fatty acids, are found in certain types of fish and can be helpful for prenatal and postnatal brain development.
About 25% of pregnant people experience anemia from iron deficiency by week 27 of pregnancy.
Dietary supplements aren't regulated in the United States the way medications are. Vitamin companies aren't required to provide extensive evidence about health benefit claims, so dosages and ingredients may vary among brands—or even be misleading. One study found that several prenatal vitamin brands were contaminated with heavy metals, while another evaluation found that mineral content levels in numerous prenatal vitamin brands varied widely. Talk to a healthcare provider if you have concerns about prenatal vitamins' ingredients.
When Should You Take Prenatal Vitamins?
Ideally, you should be taking prenatal vitamins before or as soon as it's confirmed that you're pregnant.
Experts recommend starting this routine before conception. Taking folic acid at least one month before becoming pregnant is recommended. It's also suggested that you take folic acid daily, even if you're not planning to become pregnant at the time. Taking prenatal vitamins can also reduce developing severe nausea and vomiting during pregnancy.
If you have questions about your situation, check with a healthcare provider on the best time to start taking prenatal vitamins.
While it may be a fad or trend, taking prenatal vitamins when you're not pregnant for hair growth purposes is not a scientifically backed practice. Vitamins and minerals play a role in hair growth, but experts think the hair growth differences many people experience during pregnancy are likely due to hormone changes.
Side Effects From Prenatal Vitamins
Taking too much of certain minerals can cause mild side effects, like an upset stomach or headache, or more severe side effects, like liver issues. Side effects are more likely to happen if you take a prenatal vitamin (or any vitamin, for that matter) at a higher-than-recommended dose or in addition to other different supplements.
Some of the minerals in prenatal vitamins may cause side effects such as:
Iron in prenatal vitamins can cause constipation.
DHA might lead to bloating or gas in some people.
Vitamin A may cause dry or irritated skin; in very high doses vitamin A can cause serious illness.
Zinc in higher doses can lead to nausea, dizziness, headaches, and vomiting.
Magnesium in high doses could cause diarrhea, nausea, cramping, or heart issues in extreme cases.
Some side effects, like nausea or constipation, may happen due to pregnancy and not the supplement. Make sure to take just one serving of prenatal vitamins daily, and check with a healthcare provider if you're having difficulty determining where your symptoms are coming from.
Summary
Prenatal vitamins help support the health of and replenish nutrients for the pregnant person and the growing baby. Not taking them could increase the chances of certain congenital disabilities and other health issues. Healthcare providers generally recommend starting prenatal vitamins at least a month before you plan to get pregnant.
