Medically reviewed in July 2022
For many people, eating a healthy, balanced diet is the best way to get the vitamins and minerals your body needs. But even a very healthy diet might miss out on some key nutrients.
The stakes are even higher when you’re pregnant or trying to become pregnant. At that point, it’s vital to fill those gaps with a prenatal vitamin. Nutrients found in prenatal vitamins—like folic acid, iron, calcium and vitamin D, among others—are necessary for the growth and development of a fetus, and many studies have linked them to reduced risk of birth defects.
Of course, it’s important to talk to your healthcare provider before starting any new vitamin or supplement, particularly when you’re pregnant, breastfeeding or trying to conceive. Your doctor will be able to recommend the best prenatal based on your pregnancy and health history. Read on to learn more about how prenatal vitamins can contribute to a healthy pregnancy.
What essential ingredients do prenatal vitamins have?
Like a daily multivitamin, a good prenatal can provide nutrients your everyday diet might be lacking. The major difference? Prenatal vitamins typically contain higher amounts of the vitamins and minerals essential to a growing baby—specifically, folic acid and iron.
“Folic acid is important in the nerve development of the fetus, protecting against neural tube defects, like spina bifida,” explains Meghan J. Freund, MD, an OBGYN with Mercy Health Physician Partners OB/GYN, East Beltline in Grand Rapids, Michigan. “Iron helps with growth and development of the fetus, and also helps mom. Because blood volume expands during pregnancy, a lot of pregnant patients become anemic. You need a prenatal because a lot of over-the-counter multivitamins don’t even contain iron.”
Adequate intake of folic acid has been linked to reduced risk of spina bifida, a birth defect affecting the spine and spinal cord, and anencephaly, the underdevelopment of the brain and skull.
According to the Centers for Disease Control and Prevention (CDC), all women of reproductive age should obtain at least 400 mcg of folic acid every day—whether they’re planning to get pregnant or not. Birth defects affecting the spine and brain usually occur three to four weeks following conception—often before a woman even knows she’s pregnant.
In addition to taking a prenatal vitamin, you can boost your daily intake of folic acid by eating foods such as:
- Leafy greens, like spinach
- Enriched pastas, rice, cereals and bread
- Nuts
- Citrus fruits
- Legumes—beans, peas, lentils
- Avocado
- Eggs
- Bananas
Iron, a mineral that helps red blood cells transport oxygen to the rest of the body, is another key nutrient in prenatal vitamins.
Not only has inadequate iron intake during pregnancy been linked to low birth weight, premature birth and maternal and infant mortality, but it can lead to anemia in the mother, too. Anemia occurs when there aren’t enough red blood cells to carry oxygen to the body’s tissues, often causing symptoms like fatigue, weakness, shortness of breath, dizziness, headaches and chest pain. Although anemia is highly treatable when caught early, it may become dangerous if left untreated.
Because blood volume increases by a whopping 30 to 50 percent during pregnancy, pregnant and nursing women should aim for 27 milligrams of iron per day. In addition to taking a prenatal vitamin, you can enjoy iron-rich foods like:
- Iron-fortified cereals and grains
- Beef and chicken
- Tuna
- Tofu
- Lentils and beans
- Spinach
Although those who eat a plant-based diet can still choose from a variety of foods with iron, the body absorbs two to three times more iron from animal sources than from plants.
Foods that contain vitamin C can help the body absorb iron more efficiently. Pair foods containing iron with fruits and veggies like strawberries, oranges, bell peppers and tomatoes.
Who should take prenatal vitamins?
Prenatal vitamins are recommended for all pregnant, as well as women of reproductive age. They may also be valuable for women who are nursing.
Groups who may need to take higher than usual amounts of prenatal vitamins are:
- Women who have already had a baby with a neural tube defect
- Those with a family history of spina bifida
- Women taking anti-epileptic medicines
- Populations with chronic conditions linked to an unbalanced diet, such as type 2 diabetes
Speak with your doctor if you fall into any of these categories.
Additionally, women with special diets, such as vegetarian or gluten-free, should talk with a doctor or dietitian to ensure their dietary needs are being met during their pregnancy.
When should I start taking prenatal vitamins—and for how long?
“Any patient who is not on birth control and could potentially get pregnant, or someone who is trying to conceive should start taking prenatal vitamins at least a few months before conception,” says Dr. Freund.
Prenatal vitamins can also be important post-pregnancy. Women with restrictive diets or those who are breastfeeding may not get adequate nutrients through diet alone. A prenatal or multivitamin may help breastfeeding mothers meet their daily nutritional needs.
What should I look for when shopping for a prenatal vitamin?
Over-the-counter prenatal vitamins are widely available in pharmacies, drugstores, grocery stores and through online retailers. Your healthcare provider can also provide a prescription. If you have a family history of neural tube defects, have given birth to a child with neural tube defect or have a medical condition like anemia, you may be advised to take additional supplements to help support your pregnancy.
In addition to folic acid and iron, look for prenatal vitamins that are high in calcium and vitamin D. These nutrients play a vital role in the development of your baby’s skeletal system and are especially important during the second and third trimesters, says Freund.
Some prenatal vitamins also have DHA, a type of omega-3 fatty acid. DHA is thought to help fetal brain and eye development. Not all prenatal vitamins have DHA, but it may be beneficial to seek one, especially if you do not eat fish or other foods high in omega-3 fatty acids.
When paired with a prenatal, you can also up your intake with foods that are high in calcium and vitamin D, like fortified dairy products, fortified orange juice, fatty fish, egg yolks, kale and broccoli.
Not all prenatal supplements are created equal though. The amount of each nutrient contained in a prenatal vitamin can vary widely by brand. A June 2019 study published by the Journal of the American Medical Association JAMA Network Open found that while prenatal supplements do help reduce inadequate intakes of important nutrients—particularly folate and iron—they can also lead to women consuming too much. However, without the use of supplements, pregnant women would likely not take in the recommended amount of either nutrient. Researchers suggest that guidance should be provided to pregnant women about selecting a supplement with a responsible formulation, along with nutritional and dietary recommendations.
Are there side effects to prenatal vitamins?
According to Freund, most women don’t experience serious side effects from prenatal vitamins. “Sometimes people have trouble swallowing pills,” she says. “Or, if they have bad nausea, especially in the first trimester, they may have an aversion to their prenatal vitamins.”
Other women may experience constipation, often due to the high amount of iron in prenatal vitamins. Drinking plenty of fluids, exercising, taking your vitamin at night and adding fiber to your diet can provide relief for some women.
However, some women may still experience discomfort. “For those patients, we recommend prenatal gummy vitamins,” she says. Since gummy vitamins often lack calcium and iron, women may need to take in additional amounts of those nutrients within their diet or through other supplements.
It is possible to take too many vitamins, which could result in vitamin toxicity. If you’re planning to conceive or already pregnant, be sure to talk to your healthcare provider before starting any vitamins, as well as mentioning any other supplements you already take. Use prenatal vitamins only as directed, typically once daily.
Remember: If you’re pregnant or trying to become pregnant, a prenatal vitamin should be a part of your daily routine. If you’re not sure which prenatal is right for you or have any questions about your diet, talk to your healthcare provider. But remember, a vitamin or supplement is never substitution for a complete and healthy diet.
“Having a healthy, balanced diet and staying adequately hydrated will lay the groundwork for a healthy, happy baby,” says Freund.
