This sheet is about exposure to diphenhydramine in pregnancy and while breastfeeding. This information is based on available published literature. It should not take the place of medical care and advice from your healthcare provider.

What is diphenhydramine?

Diphenhydramine is a medication that has been used to treat allergy symptoms, nausea, motion sickness, insomnia, itchy skin, and tremors related to Parkinson’s disease. It is in a class of medications called antihistamines. Diphenhydramine is found in many prescription and over the counter products. Some brand names for diphenhydramine include Benadryl®, Unisom®, Sominex®, and Nytol®.

Sometimes when people 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.

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

It is not known if diphenhydramine can make it harder to get pregnant.

Does taking diphenhydramine increase the chance of miscarriage?

Miscarriage is common and can occur in any pregnancy for many different reasons. Results from one study did not show an increased chance of miscarriage with the use of antihistamines, including diphenhydramine, in early pregnancy.

Does taking diphenhydramine increase the chance of birth defects?

Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. The use of diphenhydramine is not expected to increase the chance of birth defects above the background risk. A few studies have suggested a higher chance for birth defects when diphenhydramine is used during the first trimester. However, these studies do not all agree, and no consistent pattern of birth defects has been noted. There are also several studies that reported no increased chance of birth defects with the use of diphenhydramine in early pregnancy.

Does taking diphenhydramine in pregnancy increase the chance of other pregnancy-related problems?

Occasional use of diphenhydramine at recommended doses is not expected to increase the chance of other pregnancy-related problems, such as low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth). It is not known if diphenhydramine can increase the chance of preterm delivery (birth before week 37). Some studies have reported an increased chance, but the association was weak.

There are reports of other issues, including uterine contractions and, very rarely, fetal death with the use of diphenhydramine in the third trimester. However, these reports usually involve using more of the medication than is recommended or using it for longer than the recommended time.

Can I take diphenhydramine with a benzodiazepine?

There is a single human report and animal data that has suggested that the combination of a medication called temazepam (a benzodiazepine) and diphenhydramine might increase the chance of stillbirth or infant death shortly after birth. It has been recommended that these two medications not be used together during pregnancy. People taking temazepam should talk with their healthcare provider before taking diphenhydramine during their pregnancy.MotherToBaby has a fact sheet on temazepam here: .

I need to take diphenhydramine throughout my entire pregnancy. Will it cause withdrawal symptoms in my baby after birth?

The use of diphenhydramine during pregnancy can cause temporary symptoms in newborns soon after birth. These symptoms are sometimes referred to as withdrawal. There are a few reports of withdrawal symptoms (tremors and diarrhea) in infants who were exposed to diphenhydramine daily throughout pregnancy. Not all babies exposed to diphenhydramine will have these symptoms. It is important that your healthcare providers know you are taking diphenhydramine so that if symptoms occur your baby can get the care that is best for them.

Does taking diphenhydramine in pregnancy affect future behavior or learning for the child?

It is not known if diphenhydramine increases the chance for behavior or learning issues.

Breastfeeding while taking diphenhydramine:

Diphenhydramine passes into breastmilk in small amounts. This medication can cause sleepiness in adults as well as the nursing baby. Two studies that looked at the use of antihistamines such as diphenhydramine while breastfeeding reported that exposed babies were irritable, sleepier, and/or slept less. Short-term or occasional use of diphenhydramine is not expected to increase the chance of side effects during breastfeeding. If you need to take an antihistamine regularly, ask your healthcare provider about which medication is best for you. Be sure to talk to your healthcare provider about all your breastfeeding questions.

If a male takes diphenhydramine, could it affect fertility or increase the chance of birth defects?

Studies have not been done to see if diphenhydramine could affect male fertility (ability to get partner pregnant) or increase the chance of birth defects above the background risk. In general, exposures that fathers or sperm donors 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/.

Selected References:

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• Aldridge T, et al. 2014. First-trimester antihistamine exposure and risk of spontaneous abortion or preterm birth. Phamacoepidemiol Drug Saf. Oct 23 (10):1043-50. [PMC free article: PMC4776748] [PubMed: 24789281]
• Anderka M, et al, and the National Birth Defects Prevention Study. 2012. Medications used to treat nausea and vomiting of pregnancy and the risk of selected birth defects. Birth Defects Res (Part A) 94:22-30. [PMC free article: PMC3299087] [PubMed: 22102545]
• Aselton P, et al. 1985, First-trimester drug use and congenital disorders. Obstet Gynecol 65(4):451-455. [PubMed: 3982720]
• Brost BC, et al. 1996. Diphenhydramine overdose during pregnancy: Lessons from the past. Am J Obstet Gynecol 175:1376-7. [PubMed: 8942519]
• Black RA, et al. 2003. Over-the-Counter Medications in Pregnancy. Am Fam Physician. 67(12):2517-2524. [PubMed: 12825840]
• Brzezińska-Wcisło L, et al. 2017. Pregnancy: a therapeutic dilemma. Adv Dermatol Allergol:XXXIV (5): 433-438. [PMC free article: PMC5831277] [PubMed: 29507557]
• Chaudhry SK & Susser LC. 2018. Considerations in treating insomnia during pregnancy: a literature review. Psychosomatics, 59(4), 341-348. [PubMed: 29706359]
• 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. [PMC free article: PMC3619228] [PubMed: 19161158]
• Hansen C, et al. 2020. Use of antihistamine medications during early pregnancy and selected birth defects: The National Birth Defects Prevention Study, 1997–2011. Birth Defects Research, 112(16), 1234-1252. [PMC free article: PMC9168970] [PubMed: 32657014]
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• Kargas GA, et al. 1985. Perinatal mortality due to interaction of diphenhydramine and temazepam. N Eng J Med 313:1417-8. [PubMed: 2865678]
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• Miller MA, et al. 2020. Sleep pharmacotherapy for common sleep disorders in pregnancy and lactation. Chest, 157(1), 184-197. [PMC free article: PMC6965691] [PubMed: 31622589]
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• Moretti ME, et al. 1995. Adverse events in breastfed infants exposed to antihistamines in maternal milk. Reprod Toxicol 9: 588.
• O'Brien TE. 1974. Excretion of drugs in human milk. Am J Hosp Pharm 31:844-54. [PubMed: 4608122]
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• Spencer JP, et al. 2001. Medications in the Breast-feeding Mother. Am Fam Physician 64(1): 119-127. [PubMed: 11456429]

“OTIS/MotherToBaby encourages inclusive and person-centered language. While our name still contains a reference to mothers, we are updating our resources with more inclusive terms. Use of the term mother or maternal refers to a person who is pregnant. Use of the term father or paternal refers to a person who contributes sperm.