Is Aspartame Really Safe During Pregnancy? Risks Explained

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Artificial sweeteners are relatively new ingredients and are a common concern for many women, especially while pregnant. With all of the sweeteners available, how does aspartame stack up and what are the potential risks?

One of the most popular and widely available artificial sweeteners, aspartame is known to be safe to use while pregnant. The sweetener presents little risk. However, aspartame also doesn’t contribute much nutritionally and is best consumed in moderation.

With all of the conflicting information surrounding aspartame, I sifted through the research and recommendations to break down exactly what the concerns about aspartame are all about and how you can choose the best sweetener for you.

Can Pregnant Women Have Aspartame? Is It Safe?

There is a lot of confusion and controversy surrounding artificial sweeteners, especially aspartame.

Despite the controversy, aspartame is also one of the most common non-nutritive sweeteners. A couple of the brand names for aspartame sweeteners you might find are NutraSweet and Equal, which is a blend of several sweeteners including aspartame. Aspartame is also known as additive E951 in Europe.

Non-nutritive sweeteners are exactly what their name suggests. They contribute sweetness but do not provide any nutritional value.

Aspartame is most commonly found in sugar-free desserts, gum, and sodas, and other low-calorie drinks. The famous Diet Coke is sweetened with a blend of aspartame and a couple of other sweeteners.

woman adding artificial sweetener to a drink

If you look at the label on an aspartame-sweetened food, you may notice a disclaimer stating that they are not suitable for folks with PKU (phenylketonuria). PKU is a rare genetic and metabolic disorder that causes the body to be unable to break down phenylalanine, which is an amino acid found in aspartame.

This disclaimer catches many label-savvy shoppers off guard and may even mislead them to believe that aspartame isn’t safe for pregnant women. However, the disclaimer is simply meant to alert those with the specific medical condition of PKU that aspartame is an ingredient in the particular food or drink and does not make any safety claims for the general public (source: Johns Hopkins All Children’s Hospital).

Despite any controversy or confusion, the US Food and Drug Administration (FDA) lists aspartame as a safe sweetener to consume during pregnancy (source: American Pregnancy Association).

The FDA’s official position on aspartame is backed up by scientific research. While the byproducts of aspartame breakdown do cross the placenta, both human and animal studies have verified that there are no harmful effects on the baby’s health (source: Canadian Family Physicians).

One study even showed that there were no adverse effects for mom or baby when mom consumed four to five times the acceptable daily intake (source: International Journal of Fertility).

pregnant woman drinking tea

Like many other non-nutritive sweeteners, the foods and beverages where aspartame is an ingredient are typically advised to be enjoyed in moderation. These foods also usually do not provide much nutritionally.

Unless your healthcare provider has prescribed you to severely limit added sugar or control your blood sugar, there is no reason to restrict yourself to only artificial or low-calorie sweeteners, especially during pregnancy.

What Are the Risks or Side Effects of Aspartame During Pregnancy?

Aspartame and other artificial sweeteners have been the subject of many research studies over the years, aimed at evaluating their safety, including any risks for pregnant women and their unborn babies.

During digestion, aspartame breaks down into three separate products: aspartic acid, phenylalanine, and methanol. The latter, methanol, is what leads to concern over risks or side effects.

While methanol is produced during digestion of aspartame, the amount produced is such a small amount that has no adverse effects on adults, children, or fetuses (source: Canadian Family Physicians).

This was shown to be true for babies in utero even when the mom consumed far more than the acceptable daily intake (source: International Journal of Fertility).

Aspartame tablets and tea

In 2016, scientists showed a connection between expectant moms who consumed artificial sweeteners during pregnancy and babies with higher BMI z-scores. This association was only seen in babies born to moms who drank artificially sweetened drinks daily and the BMI z-score was less than a quarter-point higher.

However, this study was also generalized to all artificial sweeteners, not specifically aspartame, and the results have yet to be replicated (source: JAMA Pediatrics). The researchers also did not look at the child’s growth and development after 1 year of age, meaning the babies may have gone on to grow and develop as perfectly healthy children. 

Despite all of the research, there is no definitive link between aspartame and any adverse effects for mom or baby, and in moderate amounts aspartame is still considered to be safe during pregnancy.

Can Aspartame Cause Birth Defects or Autism?

As I mentioned earlier, there are no known adverse effects on baby’s health and development that are caused by mom consuming aspartame during her pregnancy.

This includes birth defects, and was shown to be true even when mothers consumed four to five times the acceptable daily limit of aspartame (source: International Journal of Fertility).

While none of the studies looked specifically at the first trimester, the fact that aspartame is rated as safe, as well as there being no connection between the sweetener and birth defects means that it is unlikely that aspartame would have any first-trimester specific effects.

Another question many women ask is whether or not there is a connection between autism and artificial sweeteners, including aspartame in particular. Man-made food ingredients are a common scapegoat, though currently there are no known causes of autism spectrum disorder and no links to particular food ingredients.

sugar and artificial sweetener in bowls

How Much Aspartame is Pregnancy-Safe? Plus Alternatives

If you read the above sections closely, you may have noticed a couple of references to the “acceptable daily intake.” The World Health Organization (WHO) recommends a daily limit of no more than 40 milligrams of aspartame per kilogram of body weight for everyone, including pregnant women (source: Canadian Family Physicians).

For a 150 pound (or 68 kilogram) woman, this equals 2,270 milligrams of aspartame. Compare this to the 125 milligrams of aspartame in a 12-ounce can of Diet Coke (source: Diabetes Self Management). This means that to reach the recommended aspartame limit, it would take nearly 22 cans of the soda! – way more than the recommended limit of drinking soda “in moderation”. For more on soda safety, read this article.

Women with gestational diabetes may reach for aspartame-containing foods and drinks more often, since they don’t impact blood sugar. While reaching the acceptable daily intake may prove difficult, there are also alternatives to aspartame available if you find yourself choosing these foods more often than not.

A few non-nutritive sweeteners are plant-based, including stevia and monk fruit. While the human body doesn’t see a big difference between artificial and naturally occurring non-nutritive sweeteners, a plant-based sugar substitute more closely aligns with some women’s lifestyles.

There is no need to replace all of the aspartame in your diet with alternative sweeteners, but there is one place where a substitution can be very useful.

When it comes to chewing gum, a good alternative is the sugar-alcohol, xylitol. Xylitol is popular in gums and mouthwash as it’s antimicrobial and actually reduces plaque and risk of dental cavities! (source: Journal of Natural Science, Biology, and Medicine)!

Keep in mind that aspartame does not cause cavities, but xylitol is a helpful swap if you are trying to improve your oral health. You can read more about chewing gum (or accidentally swallowing it) during pregnancy here.

pregnant stomach

Which is Better in Pregnancy, Aspartame or Sucralose?

There are a lot of sweetener options on the market and choosing the “best” one for you can get confusing.

Aspartame and sucralose are often compared, as they are two of the most similar products. Both sweeteners are man-made and are found in a variety of “light” or calorie-free foods and drinks.

Unlike sugar alcohols, neither aspartame or sucralose attract water to the digestive tract. Therefore, sucralose or aspartame are much less likely to lead to diarrhea so they may be better tolerated by some folks.

Neither sweetener is associated with negative effects on mom or baby and are both safe to use while pregnant. Since both sweeteners are safe and neither is better than the other- which one to use comes down to personal preference.

For a more in-depth look at the safety, daily limit, and other considerations of sucralose use during pregnancy check out our dedicated sucralose article for pregnant women.

Replacing “real” sugar with artificial sweeteners is also not necessary. Artificially sweetened foods can be especially helpful if you need to limit sugar or control blood sugar levels for medical reasons, but when it comes to making a batch of brownies real sugar can definitely still do the trick and be part of a healthy diet.

Overall, aspartame (AKA NutraSweet and Equal) is a man-made sweetener. Found in many “light” or low-calorie foods and drinks, aspartame does not raise blood sugar or contribute much in the way of nutrition.

Research has backed up the FDA’s official stance that aspartame is a safe sweetener option for both mom and baby during pregnancy. Even at four to five times the acceptable daily intake no birth defects or other adverse effects have been linked to enjoying foods made with aspartame.

To be on the safe side, again, it is recommended to limit daily consumption to 40 milligrams of aspartame per kilogram of body weight.