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

What is chlorpheniramine?

Chlorpheniramine is an antihistamine. Antihistamines are medications used for allergies and colds. Chlorpheniramine is used to relieve allergy symptoms, including sneezing, runny nose, watery eyes and itchy throat. Chlorpheniramine is sold under brand names that include Chlor-Trimeton®. Chlorpheniramine has been in prescription and over-the-counter medications. There is a range in the doses of chlorpheniramine found in over the counter products.

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

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

I just found out I am pregnant. Should I stop taking chlorpheniramine?

Talk with your healthcare providers before making any changes to this medication.

Does taking chlorpheniramine increase the chance for miscarriage? 

Miscarriage can occur in any pregnancy. We have not located studies that try to see if chlorpheniramine has any effect on human fertility.

Can taking chlorpheniramine during pregnancy cause 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. It is unlikely that chlorpheniramine would cause an increased chance for birth defects. Most studies find no overall increased chance of birth defects with the use of chlorpheniramine in early pregnancy. While two studies found a small increased chance for different types of birth defects, no pattern has been detected. At this time, reports describing birth defects with first trimester chlorpheniramine cannot be considered proof of risk and it is likely that these problems were due to chance.

Can use of chlorpheniramine cause other pregnancy complications?

Studies have not been done to see if chlorpheniramine might increase the chance for pregnancy complications.

Can I breastfeed while taking chlorpheniramine?

Chlorpheniramine is sold in a wide range of doses. Small doses (2mg to 4 mg), taken occasionally, should be fine to take while breastfeeding. However, there is not enough information to know how larger doses or taking daily small doses would affect the nursing child or the woman’s milk production.

Chlorpheniramine can cause sleepiness in adults, and it is possible that in higher doses, it may do the same for a nursing baby. For this reason it may not be a preferred antihistamine for long-term use during breastfeeding. If you need to take an antihistamine regularly while breastfeeding, ask your healthcare provider if another medication might work for your symptoms.

It is possible, but not proven, that antihistamines in general may lower the amount of milk a woman makes. This might be more likely to happen when used in combination with a decongestant like pseudoephedrine or phenylephrine, or if used before breastfeeding is established.

When five women were asked about their infant’s behavior after the mother used chlorpheniramine and breastfed, the mothers did not report any symptoms in their babies.

Be sure to talk to your healthcare provider about all of your breastfeeding questions.

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

In general, exposures that fathers have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures and Pregnancy at

Selected References:

  • Aselton P, et al. 1985. First-trimester drug use and congenital disorders. Obstet Gynecol 65(4):451-455.
  • Diav-Citrin O, et al. 2003. Pregnancy outcome after gestational exposure to loratadine or antihistamines: a prospective controlled cohort study. J Allergy Clin Immunol 111(6):1239-1243.
  • Gilboa SM, et al. 2009. National Birth Defects Prevention Study: Use of antihistamine medications during early pregnancy and isolated major malformations. Birth Defects Res A Clin Mol Teratol 85(2):137-150.
  • Ito S, et al. 1993. Prospective follow-up of adverse reactions in breast-fed infants exposed to maternal medication. Am J Obstet Gynecol. 168:1393-1399.
  • Jick H, et al. 1981: First-trimester drug use and congenital disorders. JAMA 246(4):343-346.
  • Li Q et al. 2013. Assessment of antihistamine use in early pregnancy and birth defects. J Allergy Clin Immunol Pract. 1(6):666-74.
  • Nelson MM and Forfar JJ. 1971. Associations between drugs administered during pregnancy and congenital abnormalities of the fetus. Br Med J. 1;523-527.