Phenylephrine and Pregnancy
It may not be safe for pregnant women to use phenylephrine. There is some concern that phenylephrine may cause constriction of blood vessels in the uterus, which may lead to inadequate oxygen delivery to the fetus. Also, if used during the first trimester, phenylephrine may cause certain birth defects. If you are taking this medication and pregnancy occurs, make sure to talk to your healthcare provider.
Phenylephrine is a medication often used as a decongestant and in emergency medicine (to treat very low blood pressure). This medication may not be safe for use during pregnancy, although the full risks are not currently known.
The U.S. Food and Drug Administration (FDA) uses a pregnancy category system to classify the possible risks to a fetus when a specific medicine is taken during pregnancy. Pregnancy Category C is given to medicines that have not been studied in pregnant humans, but do appear to cause harm to the fetus in animal studies. Also, medicines that have not been studied in any pregnant women or animals are automatically given a pregnancy Category C rating.
There is some concern that phenylephrine may cause constriction of blood vessels in the uterus, causing reduced blood flow in the uterus, possibly leading to inadequate oxygen delivery to the fetus.
Also, phenylephrine can cause problems when used in combination with oxytocin or other medications used to induce labor, and dangerously high blood pressure (in the mother) may result.
Preliminary studies suggest that taking phenylephrine early in pregnancy (during the first trimester) might increase the risk of certain birth defects, such as clubfoot or an umbilical hernia. More research is necessary in order to know if phenylephrine actually increases the risk of such problems.
However, it is important to note that animals do not always respond to medicines in the same way that humans do. Therefore, a pregnancy Category C medicine may be given to pregnant women if the healthcare provider believes that the benefits to the pregnant woman outweigh any possible risks to the unborn child.