Pregnancy in Non antihistamine safe sedating Publication No. Obstet Gynecol. Other conditions may cause similar symptoms, but they can be distinguished from allergic rhinitis by allergy testing to confirm positive allergen-specific IgE to specific triggers. There are four types of histamine receptors in the body H1-H4with H1 and H2 being most widely expressed. None of the medications in this class of drugs has been reported to increase fetal risk when used at any time during pregnancy. Allegra [product monograph] Laval, QC: The pharmacokinetics of fexofenadine in breast milk were studied in 4 lactating women taking 60 mg of terfenadine every 12 hours. In addition, pregnancy in Non antihistamine safe sedating of the antihistamines is excreted in the breast milk in an appreciable amount so as to have any adverse effects on the breastfeeding infant. It has a variety of different functions. More data are available about the various effects of the first generation antihistamines in pregnancy.