When Should You Start Taking a Prenatal Vitamin?

If you’ve ever been pregnant, you’re probably familiar with prenatal vitamins. These vitamins are specifically formulated for those who are expecting. "Prenatal vitamins are supplements that contain daily vitamins and minerals that are important for individuals to consume prior to conception and throughout pregnancy and postpartum,” says Melanie Santos, NP, a nurse practitioner at Viva Eve.

Most brands contain higher levels of vitamin B9 (folate/folic acid), iron, calcium, iodine, and DHA than traditional daily vitamins. This is because these ingredients, in particular, help both the parent and the fetus stay healthy and can help to prevent certain birth defects.

It’s important to start taking prenatal vitamins as soon as you find out you are pregnant, but ideally well before you conceive, according to the American College of Obstetricians and Gynecologists (ACOG) and Centers for Disease Control and Prevention (CDC).Here, learn all about when and how to choose a prenatal vitamin that will keep you and your baby as healthy as can be.

When to Start Taking a Prenatal Vitamin

If you’re thinking about getting pregnant within the next year, it's a great idea to do your research and find a high-quality prenatal vitamin to start as soon as possible.

"Take them right now," says Felice Gersh, MD, an OB/GYN specializing in women’s health and director of the Integrative Medical Group of Irvine, in Irvine, Calif. "I recommend prenatal vitamins to all my reproductive-aged women, whether or not making a baby is a current goal."

Not only does taking a prenatal vitamin before you start trying to conceive help optimize your health, but it also gets you in the habit of taking the pill daily.

"The idea is to be optimally healthy prior to conception," says Dr. Gersh. "From the moment of ovulation and fertilization, you want everything perfect. That requires getting an optimal array of nutrients into the body, in order to optimize hormones, control inflammation, nurture the gut microbiome, and promote and support the ability of cells to perform essential functions."

Some healthcare providers recommend starting a prenatal vitamin three to six months prior to trying to conceive. Organizations like ACOG and the CDC stress that it's important to start taking folic acid, specifically, at least one month prior to becoming pregnant. Be sure to speak to your OB/GYN or primary care provider early and often so that they can recommend the best course of action for you.

If you haven’t started taking prenatal vitamins prior to learning you were pregnant, don’t panic. The vitamins that are typical in prenatal vitamins are also found in foods, so as long as your diet consists of a variety of fruits, vegetables, leafy greens, whole grains, and beans, your nutritional needs are likely at an adequate level. But do start a prenatal vitamin regimen as soon as possible.

“Many women only find out they are pregnant after they miss their period, which can be around four to six weeks of pregnancy,” says Santos. “Once you find out you are pregnant, you should begin taking prenatal vitamins daily thereafter.”

Benefits of Prenatal Vitamins

Prenatal vitamins are important for your baby's proper development. “The main purpose is to reduce neural tube defects—a type of very serious birth defect—in babies,” says Dr. Gersh.

The most common neural tube defect is spina bifida, which affects about 1,500 babies born each year in the United States. Folic acid decreases the risk of a birth defect substantially.

The iron in prenatal vitamins is also essential to your baby's growth. “Blood volume doubles in pregnancy so adequate iron intake is essential to prevent anemia and to support the development of the placenta and fetus,” says Sari Imberman, MS, RD, founder of Fun With Food, a service that helps parents raise children with happy and healthy dietary habits. 

Prenatal vitamins have also been shown to lower the risk of preterm labor, a low birth weight, and preeclampsia. “Other benefits are a better mood for the parent, stronger hair, detoxification, and blood production," says Dr. Gersh.

They may help with morning sickness, too. “Studies have shown that women who take prenatal vitamins at least three months prior to conception experience less nausea in their first trimester of pregnancy,” says Santos.

Prenatal vitamins can be beneficial in the postpartum period, too. “Continuing the prenatal vitamin in postpartum and while breastfeeding is also advised to keep mom’s body well-nourished and able to produce nutrient-rich breastmilk,” says Imberman.

How to Pick a Prenatal Vitamin

Most brands of prenatal vitamins will be safe to take, but do note that like all supplements, prenatal vitamins are not regulated by the Food and Drug Administration (FDA). When choosing, there are some key things to look for on the label.

“Most prenatal vitamins contain all the necessary vitamins and minerals needed for a healthy pregnancy,” says Santos. However, it's always a good idea to ensure that the prenatal vitamin you are choosing has certain essential supplements, starting with folic acid.

Santos says your vitamin should contain 400 mcg of folic acid, but you should talk to your provider about this, as different conditions call for an increase in the amount of folic acid, such as a history of neural tube defects.

Iron is another important ingredient. “Calcium inhibits the absorption of iron, so you’ll notice that if your vitamin has adequate iron, it will likely have very little calcium,” says Imberman. “For this reason, if there is a concern about calcium in the diet, you can take a calcium supplement. Be sure to take it at a different time of day (at least two hours apart) than you take the other vitamin,” she notes.

Santos says to also look for vitamins containing 200 mg of DHA and 150 mcg of iodine. There are also certain vitamins you don’t need massive amounts of in a prenatal. One is biotin. The FDA actually lowered the recommended daily allowance of biotin to just 30 mcg in 2020.

Dr. Gersh adds that manufacturing procedures are available either on the bottle’s label or on the brand’s website. Look them up. She also advises sticking to a brand that has no added dyes or preservatives. "Don’t cut corners on the prenatal vitamin—get the best,” she says.

What to Do If Your Prenatal Vitamin Makes You Nauseous

Unfortunately, prenatal vitamins, which are so crucial to a developing baby, can also be a hard pill to swallow—literally.

“Prenatal vitamins can cause varying degrees of nausea in certain individuals,” says Santos. “More often than not, the culprit tends to be iron. The recommended dose of iron in pregnancy is 27 mg per day, so be sure to check the label on your prenatal vitamins to make sure there is not a higher dose in the pill.”

Santos recommends trying to take your prenatal vitamin at night, when nausea tends to be lower, or switching to a gummy option. (Imberman points out that gummies may have added sugar, and you need to be mindful of that if you have gestational diabetes.)

It may take some trial and error to find a time that won’t upset your stomach. “Try taking them with dinner or even at bedtime,” urges Dr. Gersh. “Hydrate well when taking them. Try with food. Try without. Just keep trying!”

If you can’t tolerate any brand or cannot afford to take them throughout your pregnancy, talk to your doctor. You should also strive to get the necessary nutrients from your diet. “Aim to get a lot of healthy fats like salmon (which will give you DHA), avocado, almond butter, and olive oil," says Imberman. Beef, chicken, eggs, and spinach have iron, and dark leafy greens contain both iron and folate. Other sources of folate are beans, peanuts, sunflower seeds, avocado, broccoli, and breakfast cereals.

A Word From Verywell

Taking a prenatal vitamin is important for both the pregnant person and the developing baby. It can help prevent birth defects and replenish nutrients lost during pregnancy and the postpartum period. Many experts recommend taking prenatal vitamins before or when you start trying to conceive. If you haven’t taken any before learning you are pregnant, it is a great idea to start now. Be sure to speak with your OB/GYN or midwife if you have any additional questions about prenatal vitamins.