Antihistamines in Pregnancy

Most manufacturers of antihistamine tablets or eye drops advise to avoid use in pregnancy. However, in consulting the British National Formulary (BNF), a doctor’s trusted handbook of all UK medicines and any of their dangers, it suggests "there is no evidence of teratogenicity".

Antihistamine may be present in breast milk, and the BNF states, “ although not known to be harmful, most manufacturers advise avoiding their use in mothers who are breast feeding". So breast feeding is more of a judgement call.

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 or in mothers who are breast feeding, rather than ones that can cause drowsiness, such as chlorphenamine, commonly sold as the brand Piriton, as they can cause "irritation or excitability to your baby" if late in the third trimester.

Sodium cromoglicate eye drops do not contain antihistamine. Little is absorbed into the body. While over-the-counter products say to consult your doctor before taking, the BNF states they are not known to be harmful in pregnancy and are unlikely to be present in breast milk, so are suitable for both, after discussion with your doctor.

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 these days 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, preventing it entering the nose and provoking an immune response. You could apply Vaseline around the nostrils or Haymax hay fever balm.

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

Saline nasal lavage can help to wash away allergens including pollen from the nasal cavity, which may reduce ongoing irritation.

Eyelid wipes or eye washes can do a similar job for the eyes.

Red light therapy devices are thought to suppress the mast cells that release histamine, thereby reducing hay fever symptoms.

Soothing the eyes can reduce eye symptoms - Optrex Sore eye drops 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. The BNF refers to the safety of these when used as an asthma inhaler – where the steroid dose may higher be than in nasal sprays – and states, “inhaled drugs for asthma can be taken as normal during pregnancy and breastfeeding".

Again, a pharmacist won’t sell these directly to you, and you should seek advice from your doctor about your particular medical conditions and any concerns before starting them.

Decongestants are 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. The BNF states 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.