Prenatal Vitamins: Why Folic Acid? What NOT to Take?

Prenatal vitamins: Why folic acid? What not to take.

You’re newly pregnant, and one of the first pieces of advice you get is to start taking a prenatal vitamin. Is this necessary? Can you just eat a healthy diet instead? What’s all the buzz about folic acid in pregnancy? Are all vitamins good, or are there some you should avoid? Let’s talk about nutritional needs during pregnancy and how prenatal vitamins help meet those needs.

Estimated reading time: 7 minutes

What are prenatal vitamins?

During pregnancy, your nutritional needs increase to support the growth of your baby. This includes an increased need for vitamins and minerals, such as calcium, zinc, and vitamin C. While no supplement can replace a healthy diet, doctors recommend that pregnant women take a daily prenatal vitamin in addition to nutritious eating. Prenatal vitamins are vitamins that are made specifically for pregnant women.

Important players in your prenatal vitamin

Let’s discuss the key players in your prenatal vitamin. While the vitamins listed below often take the spotlight, there are a number of other vitamins we aren’t featuring that you need more of during pregnancy, too. If you’re interested in further reading, March of Dimes has a great resource to learn more about what they are and what they do.

Folic Acid (Vitamin B9)

What is folic acid?

You hear so much about folic acid in pregnancy, but may wonder what it is and why it’s such a big deal. Folate is a B vitamin that’s found naturally in foods such as leafy greens and some fruits (1). Folate that is produced synthetically is called folic acid.

How much folic acid should I take?

Doctors recommend that you take a daily folic acid supplement of 600 micrograms during pregnancy. Some providers recommend that all women of childbearing age take 400 micrograms daily even when not pregnant, and especially urge women who are trying to conceive to start supplementing before becoming pregnant (1). While a healthy diet probably includes some foods rich in folate, it is difficult to get the recommended amount through diet alone.

Why is folic acid important in pregnancy?

Taking folic acid before pregnancy and in early pregnancy can help reduce the risk of certain birth defects. Specifically, it may help protect your baby against neural-tube defects, which are birth defects of the spine and brain (2). These defects include spina bifida and anencephaly. These conditions are caused when the coverings of the spinal cord do not close completely during prenatal development (3). Research has established that supplementing with folic acid decreases the prevalence of neural tube defects.


What is iron?

Did you know that your blood volume increases by 40 – 50% when you’re pregnant (3)? Iron is a mineral that’s essential to blood production. It’s key to making all of that extra blood that you and your baby need during pregnancy. Iron is also important for transporting oxygen in the blood and for the healthy growth of your baby and placenta.

How much iron should I take?

Most women don’t have enough iron stores to prevent mineral deficiency, which is why prenatal vitamins include iron. The recommended dose during pregnancy is 27 mg a day, which should be covered by any prenatal vitamin. Without enough iron, women experience anemia — a condition marked by fatigue and weakness.

Side effects of taking iron in pregnancy

Many women complain of negative side effects from the iron in their prenatal vitamin, including constipation, diarrhea, or nausea. While uncomfortable, these symptoms are not harmful to you or your baby. Talk with your doctor if the symptoms worsen or don’t improve with time.

What Vitamins Not to Take

Vitamins are typically viewed as healthy and nourishing. And while this is generally true, more of a good thing doesn’t always equate with “better.” There are some vitamins that you should not get too much of during pregnancy. Take only one prenatal vitamin a day, and don’t take it along with any other vitamins, multivitamins, or supplements without first talking to your doctor or midwife.

Vitamin A

What is vitamin A?

Vitamin A is good for you — it is essential to human reproduction and helps form and maintain healthy teeth and bones, soft tissue, and skin (1, 2). It is rare for people who live in North America to be deficient in Vitamin A. The far greater concern is getting too much of it before pregnancy and in the first couple months of pregnancy.

What are the risks of too much vitamin A in pregnancy?

You can overwhelm your body with vitamin A by taking large-dose vitamins, or by the long-term use of certain acne treatments or retinol skin creams. High levels of vitamin A in early pregnancy are linked with increased rates of birth defects that affect baby’s eyes, skull, lungs, and heart. Too much can also lead to liver damage, as excess vitamin A is stored in the liver (4).

Vitamin E

What is vitamin E?

Like vitamin A, vitamin E helps with vision, reproduction, and helps keep your blood and brain healthy. It also has antioxidant properties and aids in immune function and gene expression.

What are the risks of too much vitamin E in pregnancy?

While the verdict is still out, most providers agree that supplementing with vitamin E should be avoided in pregnancy. It’s associated with complications such as very early rupture of membranes and an increased risk of abdominal pain (5). It’s best to avoid taking vitamin E supplements alone or in combination during pregnancy.

Accidentally Took 2 Prenatal Vitamins

In the midst of a busy daily routine, sometimes pregnant women accidentally double up on taking prenatal vitamins. Should you be worried? You shouldn’t take two vitamins a day regularly; it isn’t a case where more is better. But the good news — doubling up on occasion isn’t a cause for concern. If you realize that you’ve taken two on a given day, there’s no need for worry. Just go back to taking a single vitamin tomorrow.

On the other hand, regularly taking extra vitamins can cause stress on your liver, which metabolizes and stores fat-soluable vitamins (A, D, E, K) for future use. And although less serious, taking too many vitamins can also cause you nausea, upset stomach, or constipation.

Missed Prenatal Vitamin

What if you realize that you forgot to take your prenatal vitamin? Again, no worries. Missing a day isn’t something to beat yourself up over. Just do your best to remember tomorrow. And don’t take two the next day to compensate for a missed dose.

If you find that you’re having a hard time remembering to take your vitamins, try pairing it with something you always do daily. Maybe you have a banana every morning. Keep your prenatal vitamins next to the fruit bowl so you’ll see them when you get breakfast. Or perhaps you wear contacts. Put the bottle next to your contact case. If you are a person who uses electronics regularly, you can try setting an alarm or reminder in your phone.

Prenatal Vitamins & Constipation

Even without vitamins, constipation is something that many women deal with during pregnancy. It is thought to largely be the result of hormones relaxing the intestines and making everything a little sluggish. As we discussed, some vitamins and supplements, particularly iron, are known to cause constipation.

3 simple tips to help ease constipation include:

  1. Drink plenty of water to prevent the stool from becoming too hard to pass without straining
  2. Eat a fiber-rich diet to add bulk to the stool and make it more likely that it will move through your system
  3. Exercise regularly — it encourages peristalsis, or the contraction and movement of the bowels.

(Also, check out our Week 15 Pregnancy post where we discuss constipation in more detail.) Talk to your healthcare provider if it becomes too uncomfortable or if none of these remedies help.

Kopa Birth’s online birthing classes allow you to prepare for a natural hospital birth from the comfort of your own home, 24/7. Enroll today in our free online childbirth class and start preparing for your natural birth!


  1. Simkin, P. (2010). Pregnancy, Childbirth and the Newborn, 4th edition. Meadowbrook Press
  2. Glade, B.C., Schuler, J. (2011). Your Pregnancy Week by Week, 7th edition. First Da Capo Press
  3. The American College of Obstetricians and Gynecologists. (2010). Your Pregnancy and Childbirth Month to Month, 5th edition
  4. Healthline. (2019). Supplements During Pregnancy: What’s Safe and What’s Not. [online] Available at:
  5. Rumbold A, Ota E, Hori H, Miyazaki C, Crowther CA. Vitamin E supplementation in pregnancy. Cochrane Database of Systematic Reviews 2015, Issue 9. Art. No.: CD004069. DOI: 10.1002/14651858.CD004069.pub3

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Meet Katie Griffin

I’m a registered nurse, Lamaze certified childbirth educator, and the mother of 7. I help women realize their dream of a natural, intimate, and empowering hospital birth.

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You’re newly pregnant, and one of the first pieces of advice you get is to start taking a prenatal vitamin. Is this necessary? Can you just eat a healthy diet