Many people follow low-carb diets for certain benefits such as weight-loss and the improvement of certain conditions such as metabolic syndrome, diabetes, high blood pressure, and cardiovascular disease. Lately, there have been a lot of health and nutrition articles about the effects of low-carb diets during pregnancy. A recent study showed a suggested correlation between low-carb diets and the risk of birth defects. And health journalists took those findings and ran with them. But is it the lack of carbs increasing these risks or something else entirely? How many carbs do women actually need during pregnancy?

A Background on NTD and Folic Acid

Neural tube defect (NTD) is a group of birth defects that affect over roughly 300,000 births each year. They include spina bifida, anencephaly, encephalocele, and iniencephaly. This group of birth defects was becoming more and more popular and in the 80s and 90s, scientists were finding a correlation to folic acid. In 1998, the US government began mandating cereals and grains to be fortified with folic acid. Which worked for a bit, but as low-carb diets became and continue to be popular, it wasn’t enough.

Women who follow low carb diets typically consume fewer carb-based processed foods fortified with folic acid. Researchers speculated that because of this, those women would have lower folate levels compared to women who didn’t restrict their carbs. Further speculation caused many to think that lower levels of folate had to correlate to increased risks in NTDs. This is how that study came to fruition. And although the media is reporting the findings, they aren’t reporting some of the flaws of the study.

Analyzing the Study

In this study, researchers analyzed data from the National Birth Defects Prevention Study for infants conceived between 1998 and 2011. The study included 1,740 mothers of infants, stillbirths, and terminations with cases of anencephaly or spina bifida. It also looked at 9,545 mothers of control infants born without birth defects. The study found that women who consumed less than 95 grams of carbohydrate per day prior to conception were 30 percent more likely to have an infant with a neural tube defect (1).

The Study Shortcomings: FFQs

There are some issues other scientists and health professionals have issues with in regards to the study. The first being the “food frequency questionnaire” (FFQs). This questionnaire contained only 58 food items, which is already pretty limited. Participants were asked to recall what they’d consumed during the entire year before their pregnancy. (Note before pregnancy, not during). Most of us can barely recall what we ate for lunch yesterday. Imagine the difficulty and inaccuracy of trying to remember what you ate (and the frequency of what you ate) for every meal for an entire year. To the study’s credit, however, the authors do at least acknowledge that the FFQs are pretty shaky and unreliable. They wrote:

“As nutrient intakes were estimated based on self-reported frequency of specific food items using an abbreviated FFQ, we further caution against interpreting the estimated nutrient values in this study as absolute values; we cannot assume, for example, that all women classified in our study as having restricted carbohydrate intake actually consumed fewer than 95 g/day.”

How Many Carbs Are Needed During Pregnancy?

There are only a few studies that have looked at carbohydrate restriction and how this affects the health of offspring later in life, but in general, they don’t favor low-carb diets.

  • One study in humans found that the offspring of mothers who had consumed higher levels of protein and fat (likely resulting in lower carbohydrate intake) had significantly reduced insulin production in response to a glucose challenge 40 years later. For mothers consuming adequate protein, there was also an average 9.3 mm Hg increase in adult blood pressure for each 100-gram decrease in maternal carbohydrate intake (Read Study Here).
  • A similar study found that a high-protein, low-carbohydrate diet during pregnancy was associated with increased cortisol levels in the offspring 30 years later (Read Study Here). (Unfortunately, these studies did not report micronutrient intakes.)
  • Animal studies have suggested that a ketogenic diet during pregnancy may reduce the size of brain regions like the hippocampus in offspring, while increasing the size of others, such as the hypothalamus (Read Study Here).

It’s About Folic Acid 

Remember how in 1998, the government began mandating cereals and grains be fortified with folic acid? Where was folic acid mentioned in the study? Moms-to-be should focus less on carbs on more on the real deal, folate! Even on a low carb diet, there are ways to get folate levels up. The ultimate superfoods for pregnant women and their developing baby are:

  • Grass-fed beef liver
  • Grass-fed bone marrow
  • Wild-caught fish eggs
  • Pastured raised eggs (especially the yolk)
  • Fermented veggies like kimchi and sauerkraut
  • Leafy greens like spinach, broccoli, and brussels sprouts

Please note there is new research showing that many folic acid supplements are not absorbable by people diagnosed with MTHFR (methylenetetrahydrofolate reductase). This is a genetic issue that is popping up among function medicine practices. Nutritional frontiers supplements have quatrafolate which is a form of folic acid that IS absorbable.

One Final Fair Consideration

We do want to point out that neural tube development takes place extremely early on in the pregnancy. So early that it’s during the few weeks woman isn’t even aware of the pregnancy. So, any dramatic diet changes may not have a huge effect during that time. However, even ceding this point, this is still incredibly unreliable evidence on which to come to conclusions about low carb diets being harmful to fetal development.

Zock Chiropractic is Here to Help!

In summary, low-carb diets are not actually harmful to developing fetuses. That is, provided that micronutrient levels are still met. It’s unfortunate that we live in a world of fear-mongering headlines, so make sure that any article you read includes all the facts. And if you have questions or concerns, feel free to reach out!

All chiropractors can provide chiropractic adjustments and chiropractic care during pregnancy. However, Dr. Zock is certified in the Webster Technique.  For more reassurance, please take a look at our testimonials and see how Zock Family Chiropractic has been helping expectant mothers for years. As always, simply contact our office in Cranberry to schedule an introductory chiropractic session. There we can discuss your needs and help keep you healthy through chiropractic treatment during your pregnancy!

* This information has not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Please contact a medical professional for advice.


  1. Desrosiers TA et al. Low carbohydrate diets may increase risk of neural tube defects. Birth Defects Res. 2018 Jan 25.

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