This sheet is about exposure to promethazine in pregnancy and while breastfeeding. This information is based on published research studies. It should not take the place of medical care and advice from your healthcare provider.
What is promethazine?
Promethazine is a medication that has been used to treat nausea and vomiting, motion sickness, and allergies. It has also been used for sedation (to help sleep) and for treating vertigo (a feeling of motion or spinning). Promethazine is sold under brand names such as Phenergan®, Promethegan®, and Phenadoz®.
Sometimes when women find out they are pregnant, they think about changing how they take their medication, or stopping their medication altogether. However, it is important to talk with your healthcare providers before making any changes to how you take your medication. Your healthcare providers can talk with you about the benefits of treating your condition and the risks of untreated illness during pregnancy.
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/.
I take promethazine. Can it make it harder for me to get pregnant?
Studies have not been done to see if promethazine can make it harder to get pregnant.
Does taking promethazine increase the chance of miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. One small study did not report an increased chance of miscarriage after taking promethazine.
Does taking promethazine increase the chance of birth defects?
Birth defects can happen in any pregnancy for different reasons. Out of all babies born each year, about 3 out of 100 (3%) will have a birth defect. We look at research studies to try to understand if an exposure, like promethazine, might increase the chance of birth defects in a pregnancy. Taking promethazine during pregnancy is not expected to increase the chance of birth defects.
Does taking promethazine in pregnancy increase the chance of other pregnancy-related problems?
It is not known if promethazine can increase the chance of other pregnancy-related problems, such as preterm delivery (birth before week 37) or low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth).
Some reports have suggested that taking promethazine late in pregnancy might increase the chance of slowed breathing (respiratory depression) in newborns. It is important that your healthcare providers know you are taking promethazine so that if respiratory depression happens, your baby can get the care that is best for them.
Does taking promethazine in pregnancy affect future behavior or learning for the child?
It is not known if promethazine can increase the chance of behavior or learning issues. One study looked at children exposed during pregnancy to promethazine or a similar medication, ondansetron, and did not find meaningful behavior or development problems. Babies were checked at 1 week old, and children were evaluated again between the ages of about 1½ years to 5½ years old. The results grouped both medicines together, so they did not look at each drug separately.
Breastfeeding while taking promethazine:
Studies have not been done to see if promethazine can get into breastmilk. Promethazine can cause sleepiness in adults and might have the same effect in a nursing baby. If you suspect the baby has any symptoms (sleepiness or lack of energy), contact the child’s healthcare provider.
It is possible that promethazine could reduce how much milk the body makes, especially at the start of breastfeeding. If you are having trouble producing milk, talk with your healthcare provider or a lactation specialist. Be sure to talk to your healthcare provider about all your breastfeeding questions.
If a man takes promethazine, could it affect his fertility or increase the chance of birth defects?
Studies have not been done to see if promethazine could affect male fertility (ability to make healthy sperm) or increase the chance of birth defects. In general, exposures that men have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.
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