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Is It Safe to Take Diphenhydramine in Pregnancy?

By H. Lo
Updated Feb 04, 2024
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There is a need for more studies to confirm the safety of taking diphenhydramine in pregnancy. In general, though, taking diphenhydramine in pregnancy is relatively safe under certain precautions. Mainly, a woman should not take diphenhydramine in pregnancy in large doses, not use the medication habitually, and should only use it when it is clearly needed. Also, she should talk with her doctor about the benefits and risks of taking diphenhydramine prior to taking the medication. In doing so, the doctor will be able to recommend or oppose the use of diphenhydramine, depending on her current health and medical condition.

The relative safety of taking diphenhydramine in pregnancy is supported by studies conducted on animals, in which diphenhydramine failed to demonstrate a risk to an unborn baby. While as a whole, studies do not indicate conclusive harm of diphenhydramine on an unborn baby, individual cases suggest that taking the medication in high doses can prove negative. In one case, a woman who consistently took diphenhydramine in pregnancy gave birth to a baby who suffered from withdrawal symptoms five days later. For a pregnant woman herself, diphenhydramine is known to induce uterine contractions.

Before taking any medication during pregnancy, it is important to know the potential effects that it will have for both the woman and the unborn baby. While some medications might treat the pregnant woman’s symptoms, they can have adverse effects on the unborn baby. In addition, different medications can affect an unborn baby’s growth in different trimesters, with the first trimester being a very important time period in which the baby develops. As such, knowing the safety of a particular medication before taking it is crucial. Diphenhydramine is no exception and, even though it is not strictly forbidden for use in pregnancy, a pregnant woman should still be careful when taking the medication.

Similarly, medications that a woman takes can affect her baby if she is breastfeeding. When a woman takes certain medications, small quantities of the medication can pass into breast milk, which can then pose potential harm to a breastfeeding baby. In the case of diphenhydramine, the medication is found in breast milk and can even hinder a woman’s ability to lactate. The usual recommendation regarding the use of diphenhydramine is for the mother to stop breastfeeding or to stop taking the medication altogether. The decision, of course, would need to take into consideration whether the mother absolutely needs the medication for her condition.

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Discussion Comments
By fBoyle — On Dec 06, 2013

I had a bad cold when I was in my third trimester and took diphenhydramine. I got a great night's sleep, but the next day, I couldn't feel my baby moving. I panicked and went to the hospital. Everything turned out fine but I think the diphenhydramine didn't just make me drowsy and sleepy, it did the same to my baby.

If I have another child, I probably will not take diphenhydramine during pregnancy again because this was a scary incident for me.

By SarahGen — On Dec 05, 2013

@ZipLine-- Diphenhydramine is a category B drug, so it's mostly safe during pregnancy. Just don't overdo it. Don't take more than you need and stop taking it once you're better.

I took diphenhydramine when I was pregnant, but only once for allergies. I was scared about taking but I didn't really have a choice. I had a terribly itchy, allergic rash. As soon as the rash disappeared, I stopped taking it.

By ZipLine — On Dec 05, 2013

I've been suffering from allergies for a week now. I called my doctor and he said that I can take diphenhydramine once a day to relieve my symptoms. I'm so glad that this medication is okay to use in pregnancy because I feel horrible and I can't wait for my allergy symptoms to go away.

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