Antihistamines in pregnancy

Most manufacturers of antihistamine tablets or eye drops advise to avoid use in pregnancy. However, trusted drug handbooks suggest there is no evidence of teratogenicity.

Antihistamines may be present in breast milk, and the handbooks state that although they are not known to be harmful, they should be avoided by mothers who are breast feeding.

You have your own individual needs and concerns, so we would suggest you discuss this with your doctor. It would also be best to stick to non-drowsy oral versions, such as cetirizine, rather than ones that can cause drowsiness, such as chlorpheniramine, as they can cause irritation or excitability to your baby if late in the third trimester.

When a product label states "not recommended in pregnancy" or unlicensed, it can mean one of two things. Firstly, clinical trials or data collected from the public may have provided evidence of a damaging effect on you or your growing baby (often termed "teratogenicity"). These are certainly ones to avoid.

Alternatively, it may mean the drug company making the product has not done clinical trials to test for safety in pregnancy. Drug manufacturers avoid testing on pregnant or breastfeeding women, as any birth defects or harm to babies is not worth even the smallest legal risk, unless targeted specifically for them. However, data is collected by regulators and drug manufacturers on anyone pregnant or breastfeeding who has tried these anyway, and any undesirable effects are declared. Additionally, regulators have data on each of the ingredients based on other research and products, and this also guides advice.

So while the label may state that they are not recommended in pregnancy, we can review this on a product-by-product basis. In some cases, there may be no evidence to suggest a particular product causes harm to you or your growing baby. From a legal standpoint, the pharmaceutical companies let any risk lie with doctors and their patients, rather than taking on any liability.

With pregnancy, many women want to avoid taking medications, and drug-free products carry the lowest risk. They may also be enough for mild symptoms, together with practical steps to avoid pollen. Let’s consider a range of pharmacy products:

Topical nasal barriers aim to trap pollen around the nostril and stop it from entering the nose and triggering an allergic response – examples of these include Vaseline or Haymax hay fever balm.

Drug-free nasal barrier sprays are inert powders or barriers that can be sprayed up the nose to prevent the trigger of histamine release and, therefore hay fever symptoms. AllerBlock nasal spray is one example.

Saline nasal lavage (saline flushes) can sometimes help to wash away allergens, including pollen, from the nasal cavity, which may in turn reduce ongoing irritation and other allergy symptoms. Eyelid wipes can do a similar job for the eyes. Soothing the eyes can reduce eye symptoms – an example is Optrex Sore eye drops that contain witch hazel to clean and soothe the eyes.

Steroid nasal sprays, such as those containing fluticasone or beclomethasone, are not known to be harmful in pregnancy and breastfeeding. References refer to the safety of these when used as an asthma inhaler – where the steroid dose may be higher than in nasal sprays – and state that inhaled drugs for asthma can be taken as normal during pregnancy and breastfeeding.

You should seek advice from your doctor about your particular medical conditions and any concerns before starting them.

Decongestants are viewed as being unsafe in pregnancy, as they cause a narrowing of blood vessels in the nose, and carry this risk with blood flow to the placenta. Although rare, defects have been reported in growing babies in the first trimester. They may suppress lactation so it’s suggested they are avoided in breastfeeding, too.

This information is intended as a guide, so you can consider any medicated options if your symptoms are severe and not relieved by drug-free products. But we strongly advise you to speak to your doctor before taking any of these medications in pregnancy or while breastfeeding.