Rhinitis in pregnancy has been previously investigated with variable results. This study examines all the variables of the nasal airway simultaneously for the first time. Eighteen women were recruited in the first trimester of pregnancy and followed through to the postpartum period to monitor the changes that occurred. Measurements of the nasal airway included anterior rhinoscopy (AnR), peak inspiratory nasal flow, acoustic rhinometry, anterior rhinomanometry (ARM), and the saccharin test with rhinitis questionnaire scores providing a symptomatic measurement. All the tests showed a trend consistent with decreasing nasal patency when expressed as an average for the group as a whole, although only AnR, ARM, mucociliary clearance time and rhinitis questionnaire scores were statistically significant (P < or = 0.05). This confirms the effect of pregnancy on the nasal mucosa and coincides with the rise in the serum concentration of the female sex hormones with gestational age, returning to normal postpartum. Pharmacological antagonism of oestrogens may therefore relieve nasal congestion and is currently under further research.