This sheet talks about exposure to promethazine in a pregnancy and while breastfeeding. This information should not take the place of medical care and advice from your healthcare provider.

What is promethazine?

Promethazine is a medication that is used to treat nausea and vomiting, motion sickness, and allergies. It has also been used for sedation (to help sleep) and for treating vertigo. Promethazine has been sold under brand names such as Phenergan® and Promethegan®, and Phenadoz®.

I take promethazine. Can it make it harder for me to get pregnant?

Studies on women have not been done to see if promethazine could make it harder for a woman to get pregnant.

I just found out that I am pregnant. Should I stop taking promethazine?

Talk with your healthcare provider before making any changes to your medications. If you have nausea and vomiting that is affecting your daily life, please contact your healthcare provider. For more information about nausea and vomiting during pregnancy, please see the MotherToBaby fact sheet at https://mothertobaby.org/fact-sheets/nausea-vomiting-pregnancy-nvp/pdf/.

Does taking promethazine increase the chance for a miscarriage?

Miscarriage can occur in any pregnancy. One small study did not report an increased chance for miscarriage among women taking promethazine.

Does taking promethazine in the first trimester increase the chance of birth defects?

In every pregnancy a woman starts out with a 3-5% chance of having a baby with a birth defect. This is called her background risk.

Most studies do not suggest that promethazine would increase the chance for birth defects above the background risk when used in the first trimester.

Could taking promethazine in the second or third trimester cause other pregnancy complications?

Using promethazine late in pregnancy might increase the chance of slowed breathing (respiratory depression) in newborn babies. It is important that your healthcare providers know you are taking promethazine so that if respiratory depression happens your baby can get appropriate care.

Does taking promethazine in pregnancy cause long-term problems in behavior or learning for the baby?

There are a few studies looking at a small number of children whose mothers used promethazine while pregnant. Harmful effects on the children’s learning and behavior were not seen. One study included children up to 5 ½ years old.

Can I breastfeed while taking promethazine?

Promethazine has not been studied for use while breastfeeding. Promethazine can cause sleepiness in adults. It may do the same for a nursing baby. Other medications may be preferred. If you use promethazine while breastfeeding, watch your baby for sleepiness and lack of energy, and report any of these symptoms to a healthcare provider. It is possible, but not proven, that promethazine could reduce how much milk a woman makes. If you are having trouble producing milk, talk with your healthcare provider or a lactation specialist. Be sure to talk to your healthcare providers about all of your breastfeeding questions.

If a man takes promethazine, could it affect his fertility (ability to get partner pregnant) or increase the chance of birth defects?

Studies on men have not been done to see if promethazine could change a man’s ability to get his partner pregnant. In general, exposures that fathers have are unlikely to increase the chance for birth defects or other risks to a pregnancy. For more information please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/pdf/.

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