During Pregnancy, Is Diet Soda Harmful or Not?

There have been growing concerns whether diet soda may have an effect on a woman’s pregnancy. Since pregnancy is a sensitive stage in a woman’s life health wise, there are some things that just need to be avoided in order to ensure that women go through a safe and healthy pregnancy. Consuming diet soda seems to be a question mark on many pregnant women’s minds, but they do not really know why.

Is diet soda safe?

Under normal circumstances, diet soda is fairly safe to consume. It can even help women stay in shape by trying to avoid the ordinary sugar that comes with ordinary soda. But during pregnancy, there are certain issues that pregnant women should know about diet soda to fully understand if they are to be considered safe to consume. One of them is the issue about the sugar substitute used on diet sodas.


There are two types of sugar substitutes used in the manufacture of diet sodas. They are aspartame and saccharin. Aspartame is a non-caloric sweetener that is used in diet sodas and other foods. This sweetener is made up of two amino acids and is broken down by the body just like any other protein during digestion. This sweetener has been found in studies not to penetrate into the placental barrier of the fetus, hence not affecting the baby as it is developing.

Although considered safe, the sweetener aspartame may instead affect pregnant women who may have a history of a condition known as phenylketonuria or PKU. It is a rare hereditary condition where a person has trouble in metabolizing a particular protein known as phenylalanine. This protein is found in aspartame. Pregnant women should have themselves tested for PKU since high levels of phenylalanine can cause damage to the fetus.


Saccharin is another sweetener used in diet sodas. Unlike aspartame, saccharin has been found in studies to have a direct effect on the fetuses of animal models. Rats given high doses of saccharin experienced significantly higher birth defects when becoming pregnant. In this case, diet drinks containing saccharin may be something that pregnant women should avoid in order to stay safe.


Another thing worth considering with diet sodas is that some of them may contain caffeine. Caffeine is a stimulant that can raise the blood pressure and the heart rate. What’s more, caffeine can pass through the placental barrier of the fetus. This means that what can affect the mother can also affect the fetus.

Caffeine can affect the sleep patterns as well as the normal movement patterns of the baby. The fetus can’t metabolize caffeine the same way as the mother can and therefore should be avoided at all times during pregnancy.