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The Dos and Don’ts of Taking a Prenatal Supplement

There are dozens of prenatal supplements to choose from, and you may wonder how over-the-counter varieties compare to prescription supplements.

Ghofrany says women often think prescription vitamins are better, but that there’s no research to support that idea. Prescription prenatals may have more iron and folic acid, as well as other nutrients, but those levels may not be necessary for all women.

The American Congress of Obstetricians and Gynecologists recommends that pregnant women take a prenatal vitamin supplement. The group also advises all women of childbearing age to take a multivitamin supplement containing 0.4 mg of folic acid daily to reduce risk of neural tube defects in case of pregnancy. Before taking a prenatal vitamin supplement or any other type of vitamin or supplement, be sure to consult with your doctor. Prenatal supplements with high levels of nutrients are not without these potential side effects, which may be made worse by first trimester nausea and vomiting:

  • Constipation: Blame it on the excess iron in your diet. Drink plenty of water and eat high-fiber foods. Exercise on a regular basis. 
  • Queasiness: Take half a supplement pill in the morning and at night, or take the entire supplement before bed. Try taking your supplement with a meal or snack.

If you can’t relieve your discomfort, ask your doctor about taking another type of prenatal vitamin, a regular multivitamin, a chewable, or liquid vitamin. "It’s best to give women whatever form of vitamins they’ll take every day -- before and during pregnancy," Ghofrany says.

Whatever form you choose, stick to prenatal pills with reasonable amounts of vitamins, minerals, and omega-3 fats, and no herbs. There’s no reliable evidence about the safety of herbs during pregnancy. Avoid excess vitamin A. Though vitamin A is essential for growth, vision, and immunity, high vitamin A levels during pregnancy may result in birth defects. Limit supplemental vitamin A to 5,000 IU a day.