The best hay fever treatments are non-drowsy antihistamines like loratadine and cetirizine. Most over-the-counter antihistamines cause drowsiness, such as piriton, which is unsuitable for pregnant people. You should also avoid decongestant medications like Sudafed that cause blood vessels to narrow, as this can reduce the blood supply to your baby. Before taking any medication, check with your doctor or midwife to make sure it’s safe for you and your baby.