We define pregnancy rhinitis as nasal congestion in the last 6 or more weeks of pregnancy without other signs of respiratory tract infection and with no known allergic cause, disappearing completely within 2 weeks after delivery. In order to describe physiological variations of nasal obstruction during pregnancy, subjective scores and nasal as well as oral peak expiratory flow values were recorded daily in 23 pregnancies until 1 month after delivery. Scores were higher during early and late pregnancy than in the month after delivery. Objectively registered blockage increased during pregnancy in eight women only. Unexpectedly nine women showed declining blockage. Five of 23 women had pregnancy rhinitis.