Is Diphenhydramine safe during pregnancy?
What the FDA-approved label for Diphenhydramine actually states in its Pregnancy Risk Summary — not a secondhand verdict. The decision is one to make with your prescriber.
What the label’s pregnancy summary says
The label's Pregnancy section reports that animal reproduction studies in rats and rabbits (at doses up to 5 times the human dose) revealed no evidence of impaired fertility or harm to the fetus, but there are no adequate and well-controlled studies in pregnant women. Because animal studies are not always predictive of human response, the label states the drug should be used during pregnancy only if clearly needed. Discuss use in pregnancy with your prescriber.
Frequently asked questions
Is Diphenhydramine safe to take during pregnancy?
The honest answer is uncertainty: the label does not have enough pregnancy data to call Diphenhydramine safe or unsafe (summary above). That is a "decide with your prescriber" situation, weighing your condition against the unknown, not a green or red light. The one universal rule: do not start or stop a medication in pregnancy without medical advice — an untreated condition can carry its own risk to a pregnancy.
What does the FDA label say about Diphenhydramine in pregnancy?
The summary above is transcribed from the label's Pregnancy Risk Summary (§8.1). Since 2015 FDA labels replaced the old A/B/C/D/X letter categories with a narrative that describes what human and animal data actually show, which is what you are reading here — not a single letter grade.
Is Diphenhydramine safe while breastfeeding?
That is a separate question the label answers in a different section (§8.2, Lactation), and it does not always match the pregnancy verdict. This page covers pregnancy only. For breastfeeding, ask your prescriber or pharmacist, or check the NIH LactMed database, which summarizes the drug-in-breast-milk evidence.
The questions people actually ask about diphenhydramine in pregnancy
Answered by MotherToBaby, the fact sheets written by the Organization of Teratology Information Specialists and published through the NIH. Quoted in full — we do not condense them.
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?
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 diphenhydramine, might increase the chance of birth defects in a pregnancy.
A few studies have suggested a higher chance of 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 preterm delivery (birth before week 37) or low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth).
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: https://mothertobaby.org/fact-sheets/temazepam-restoril/
I need to take diphenhydramine throughout my entire pregnancy. Will it cause 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 can increase the chance of behavior or learning issues for the child.
If a man takes diphenhydramine, could it affect fertility or increase the chance of birth defects?
Studies have not been done to see if diphenhydramine could affect men’s fertility (ability to get a partner pregnant) or increase the chance of birth defects. 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/ .
Quoted from MotherToBaby Fact Sheets — Diphenhydramine, published December 2024. MotherToBaby states its fact sheets should not take the place of medical care and advice from your healthcare providers.
Breastfeeding is a separate question — what LactMed says about diphenhydramine
More guides for Diphenhydramine
Source
Diphenhydramine Hydrochloride Injection — DailyMed FDA label ↗
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The pregnancy information is transcribed from the drug’s FDA-approved label (§8.1) and mirrors what the label states — “insufficient data” is never rounded up to “safe.” This is general reference information, not medical advice. Whether to take any medication in pregnancy is a decision for you and your prescriber; do not start or stop a drug on your own, because an untreated condition can also carry risk.