It is generally safe to take a decongestant during pregnancy after the first trimester, although it is best to get approval from a doctor first. In theory, a decongestant might cause adverse effects to the fetus due to vasoconstriction, however, there is no clear connection shown in studies. A doctor will typically recommend a nasal spray decongestant during pregnancy because those are considered to be the lowest risk, although usage should be kept to a minimum. The decongestants pseudoephedrine and phenylephrine, more commonly known as Sudafed® and Sudafed PE®, are usually considered safe after the first trimester, although a pregnant woman should be aware of the possible effects on the fetus.
A decongestant causes constriction of the blood vessels in the body. This includes the arteries in the uterus, thus reducing the blood supply to the fetus. In theory, this could cause malformation and low birth weight of the fetus, although studies have not found any clear evidence. Taking a decongestant can also increase blood pressure, which can be harmful to both the mother and the fetus, especially if the mother already has high blood pressure. Although conservative use of a decongestant during pregnancy is generally safe, it is recommended that one consult a doctor prior to use.
Using a topical nasal spray decongestant during pregnancy, such as xylometazoline or oxymetazoline, is usually recommended over an oral medication because of the low risks. Only about 5% to 10% of the medication is actually absorbed into the bloodstream, and studies have not shown any increase in birth defects with use of a nasal spray decongestant. It is advised to only use the spray for a few days at a time to prevent overuse because using it too often can cause the symptoms to worsen or lead to an addiction.
Pseudoephedrine is an oral decongestant that is often considered to be safe after the first trimester as there is no indication of harm to fetus at that point. It is labeled as a category B drug according to the United States Food and Drug Administration. This means that tests of the drug on animals showed little or no fetal risks, but there either have not been sufficient studies on humans or studies have not confirmed any significant risks to a human fetus.
Some studies have shown that pseudoephedrine taken during the first trimester might cause gastroschisis, which is when the intestines of the fetus protrude from its body. Other studies, however, have shown that there is no connection between the two, so the risk of taking the decongestant during pregnancy is considered to be very low. Similarly, taking phenylephrine during the first trimester is possibly linked to minor malformations of the fetus, although not enough studies have been done on humans to confirm the association.