Prenatal Vitamins and Folic Acid: What, Why, and When

Prenatal vitamins. I feel like I had one million questions about them pre-pregnancy and in first trimester. What are they? Why are they recommended? What are the differences between available brands? When do I stop and start taking them? If I don’t take one or I forget to take one, what will happen? They make me feel sick and I can’t take them – what do I do?!

I feel like this scenario is not uncommon – you go into the doctors either when you’re just about to start trying to conceive (TTC) or right after you find out you are pregnant, and the topic comes up: prenatal vitamins. Make sure you’re taking prenatal vitamins for at least 3 months before TTC! Or, continue to take prenatal vitamins through pregnancy. But I don’t know how common it is for a physician or a care provider to actually explain why, or even what – what is in a prenatal vitamin? What about it is so important? Is it that important?!

These are all important questions and I’m sure in many cases, your care provider maybe did tell you. They did take the time to explain. I am not trying to say that every care provider overlooks this topic, just that I think not every care provider takes the time to necessarily explain or explore the topic more in-depth. Many women also won’t ask – it’s either because we’re too caught up in the excitement (or anxiety and stress) of TTC and pregnancy or because we don’t want to ask a “stupid” question (newsflash: and I repeat, no question about your health is a stupid question – ask away!). I think many of us are on autopilot either way. They say to take a prenatal vitamin? Must be for a good reason.

And that’s not wrong. However, it’s important to be informed – yes, even about the vitamins you’re taking because as I’ve discussed before, supplements are still something of concern in regards to pre-existing health conditions or medications you may be taking (I’m not saying this applies directly to prenatal vitamins, but just in an overall sense). As they say, knowledge is power. Especially when it comes to your health.

*Disclaimer: This blog is intended for informational purposes only. The information on this blog should not be used as a substitute to medical advice or medical treatment. As always, your Primary Care Provider, a doctor, or another health professional is your best resource for specific questions and medical advice. If you believe you or a loved one are experiencing a medical emergency, please contact 911.*

A Quick FYI Regarding This Post:
I think this was one of the most difficult information posts I’ve ever had to write, and that is because there is still a lot of debate around l-methylfolate use for those with MTHFR. I am not here to say one thing or the other – as always, I implore you to chat with your HCP if you have an MTHFR variant that you are aware of. This is the best option.

At this time, the recommendations from the CDC, SOGC, Health Canada, and ACOG is as I’ve described below. At the end of the article, I will provide some new studies that show l-methylfolate in a very promising light – however at this time, the official recommendation is that the evidence re: reduction of risk for NTDs applies only to folic acid. Please discuss any questions or concerns with your physician. Thank you!

So what is a prenatal vitamin? What’s in that capsule or pill?

They are a multivitamin when it comes down to it – they contain both vitamins and minerals that are important for our body to have when we are TTC and when we are growing a baby.

The amount of each vitamin or mineral will vary depending on the brand and whether or not you get them over the counter (at least in Canada) because there are also prescription prenatal vitamins.

Lets look at a popular brand of prenatal, Materna, for example. The nutritional information is available on Nestlé Baby’s website. There are a wide range of vitamins and minerals from Vitamins A through E, to minerals like magnesium and zinc.

The vitamin that sticks out or is sort of the “most important” is folate or folic acid (please see the disclaimer above re: l-methylfolate).

And what the heck is folic acid and what is it supposed to do?

Beyond just being a vitamin, it is involved specifically in the development of your baby’s (or future baby’s) central nervous system (or their spine and brain).

You may have heard the terms “neural tube” or “neural tube defects”. In the early days of development, a neural plate forms which then folds to become the neural tube. This later becomes your baby’s brain and spine. How cool! I love embryonic and fetal development – it’s infinitely interesting.

Folic acid is involved in this development and the formation of the neural tube happens very early in pregnancy, usually within the first 6 weeks. At 6 weeks, the ends of the tube should close, leading to proper formation of the central nervous system components.

Sometimes, one opening of the tube does not close and this is known as a neural tube defect (NTD). The result is commonly either spina bifida or anencephaly (there are other less common NTDs), which impact the spine and the brain respectively.

To break them down a bit more, spina bifida occurs when the spinal cord does not develop properly and where sometimes a part of it may develop outside of the spinal vertebrae (the bones of the spine that you can feel). There are different types of spina bifida, and as a result there are varying types and degrees of symptoms. For example, with a closed neural tube defect spina bifida where the spinal cord is malformed in some way but the neural tube is closed, there are often no symptoms yet, some cases can involve paralysis and other symptoms. If you want to read more about spina bifida, check out the National Institute of Neurological Disorders and Stroke page.

Anencephaly involves malformation of the brain and the skull. Similar to spina bifida, there are different types depending on the degree of malformation (or lack of brain formation at all, as in holoacrania). Unlike forms of spina bifida, anencephaly is generally fatal. You can read more about anencephaly on the Fetal Health Foundation’s website.

It is important to note that of course, like most things, there is not one single cause. Folic acid has just been shown to be one component related to NTD risk (and it is well studied – supplementation alone could reduce up to 50% of NTDs).

Risk factors for NTDs include: previous child with NTD; some medications to control epilepsy taken by the mother; and diabetes. Genetics are of course, another major risk factor.

How common are NTDs?

In a person with no family history of NTDs, NTDs are not exceedingly common.

According to the CDC data, they only occur in ~0.1-0.2% of this population (but varies based on location and race).

If you are concerned about a family history of NTDs or are unsure about your family history, speak to your doctor – sometimes genetic counselling can be helpful in these situations. The Journal of Obstetrics and Gynecology Canada outlines risk factors well in this article as well as the impact of taking folic acid supplements.

Who should take folic acid and how much is recommended?

Please talk to your primary care provider or maternal care provider about this. Each person is different, and there are factors that may impact how much folic acid supplementation someone needs.

Generally speaking, folic acid supplementation of 0.4 mg (or 400 mcg) is recommended for women who are low-risk for NTDs and who are either actively trying to conceive or are pregnant. Actually, it is even recommended for women who are in their childbearing years, whether or not they are TTC because unplanned pregnancies happen and the biggest risk period is in early pregnancy (when women often do not know they are pregnant yet).

*Some recommendations, depending on what country you live in, may say 0.6 mg is the recommendation – please consult with your physician.*

If you are taking it pre-conception, it is recommended to take it for at least 2-3 months prior and then throughout pregnancy, until 4-6 weeks postpartum. If you are breastfeeding, then it is recommended that you continue to take folic acid supplementation until you are done breastfeeding.

Women with moderate to high risk of NTDs may need to take higher doses of folic acid. Weight may also be a factor that impacts dosage – this has been suggested by current data, so it is worth a conversation with your provider. Again – all of this should be discussed with your physician.

It is also recommended that you attempt to include folate (folic acid is the “manmade” version of naturally occurring folate – which actually pertains to several different forms of vitamin B9) in the diet. Foods such as leafy greens (Brussels sprouts, spinach, etc.) and citrus for example, contain folate. However, many foods are now also fortified with folic acid to increase intake and reduce risks. It is estimated that in the U.S. people intake on average only about 0.14 mg of folic acid from fortified foods, so this is why it is important to supplement folic acid on top of dietary intake.

Table I on this Government of Canada page has a good list of foods that are good sources of folate.

I craved citrus in the early days of pregnancy – I actually never made the connection that this could have possibly been related to my body’s need for folate until now. Interesting!!

It is recommend that only one dose of prenatal vitamin be taken a day unless you have been instructed otherwise by your physician, because there is a risk of consuming too much Vitamin A with prenatal and multivitamins vitamins. Note: folic acid can be taken on its own too, outside of a combination vitamin.

Are there risks to taking folic acid? Other benefits?

Folic acid, up to 1.0 mg per day, is not known to cause any harm to mother or baby. It is also not related to any increased (or decreased) risk of breast cancer.

It has been shown in some studies however, to decrease the risk for pre-eclampsia.

Its benefit related to pregnancy seems to relate specifically to NTDs though – a Cochrane Review from 2013 showed that it doesn’t impact other outcomes (such as preterm birth or stillbirth).

Use of over the recommended amounts have not been well studied long-term.

Notably, prenatal vitamins seem to be beneficial for your child as they grow up – studies have shown decreased risk for brain tumors and leukaemia for example. Whether or not this relates specifically to folic acid (or another vitamin/mineral in the vitamins) is not known.

There may be a relationship between high folic acid supplementation in pregnancy and children with respiratory infections and asthma.

Verdict: little to no risk, and certainly benefits.

Are all prenatal vitamins made the same?

Nope. So it is important to: 1) read the nutritional label for the supplement you are buying – make sure it says 0.4 mg of folic acid, and look for government approval (see below) 2) speak to your doctor either pre-conception or in early pregnancy about any risk factors to determine the amount you may need to take.

Some supplements may include other folates (other types of vitamin B9) – it’s important to note, as I mentioned in the quick note at the top of this article, that these have not yet been reliably shown to be related to a decreased risk for NTDs.

You should also find a prenatal that has vitamin B12 in it. Although taking folic acid at 0.4 mg a day is not likely to hide symptoms of B12 deficiency, a prenatal vitamin with B12 reduces this potential risk as well.

If you are not trying to get pregnant, you can take a multivitamin with the appropriate amount of folic acid in it, instead of a prenatal vitamin (which are generally targeted at meeting the needs of a woman who is pregnant or planning to be). As always – discuss with your primary care provider before taking any supplements, especially if you are on any medications.

If you are in Canada, you want to make sure you are purchasing a vitamin that is government approved because this ensures its safety. You can identify these items by looking for the Drug Identification Number (DIN) or Natural Product Number (NPN) on the label.

I tried my very best to find a list of some good prenatal vitamins locally – however I will work on this for a future post for reference. It will just take me some time (and hitting up some of my more knowledgeable friends!) to compile.

I do want to note here that I’ve seen a lot talk about BHT as a preservative in some prenatals. I think it is often confused with BHA. BHA is more up in the air regarding safety in large amounts as it has been shown in some studies to be carcinogenic in animals. It is still approved my the US FDA in very small amounts for food preservation, but this could certainly change in future if more evidence is presented.

BHT, although similar in some ways to BHA, is not deemed to be carcinogenic. In the amount that is used to preserve food or multivitamins, there is no evidence currently that it is harmful to humans. People like to say “well it was carcinogenic to rats” – well, if we learn anything from science it’s that animals and humans don’t always react the same way to things – so although of course this is certainly an indication that more research is needed and that we should still be cautious, it doesn’t mean that this data translates to human populations.

Does this mean that you should seek it out? No – if you can avoid it that’s great, but I also wouldn’t cause yourself mental anguish over the fact that your multivitamin or prenatal has BHT in it. You’re likely consuming other things that have preservatives as well, you just didn’t read the label yet. If you are concerned, there are many options of prenatals without BHTs – however they all will have some type of preservative or else they would not last very long. You can certainly seek out one that has a preservative you are more comfortable with.

Wait before you go – why did you mention postpartum in the title?

As I mentioned a bit earlier on in this post, it is recommended (at least in Canada) to continue to take your folic acid supplementation until 4-6 weeks postpartum. If you are breastfeeding, then you should continue to take it until you finish. This is also the recommendation from the American Academy of Pediatrics.

Why is it recommended to continue during postpartum and breastfeeding? Folic acid has other roles in our body, outside of pregnancy and for our babies. It is part of a lot of processes in the body such as red blood cell and DNA production. When we are breastfeeding especially, we are sharing our intake of folic acid with our baby so it is important to make sure we have enough.

I realize that continuing to take folic acid is debated by some sources – that women get enough folic acid from their diet, however based on the estimates provided by the CDC this is debatable based on what exactly you are consuming on a daily basis. Again – I’d recommend discussing the need to continue taking the vitamin with your care provider (or even with a Registered Dietitian), to determine what is best for you.

I hope this helped to answer some gaps in your knowledge around prenatal vitamins.

Here are the links to the current studies on l-methylfolate re: absorption in MTHFR and use to prevent NTDs. Thank you to Mama Doctor Jones for providing me with this information via Twitter – I believe she also speaks about them on her YT channel here, for those of you who do not have access to these journals.

As always, if there are any needed corrections feel free to e-mail me (see the contact page) or @ETIWblog on Twitter (you can also DM me there).