Respiratory Tract . Hormonal changes to the mucosal vasculature of the respiratory tract lead to capillary engorgement and swelling of the lining in the nose, oropharynx, larynx, and trachea. Symptoms of nasal congestion, voice change and upper respiratory tract infection may prevail throughout gestation. These symptoms can be exacerbated by fluid overload or oedema associated with pregnancy-induced hypertension (PIH) or pre-eclampsia . In such cases, manipulation of the airway can result in profuse bleeding from the nose or oropharynx; endotracheal intubation can be difficult; and only a smaller than usual endotracheal tube may fit through the larynx. Airway resistance is reduced, probably due to the progesterone-mediated relaxation of the bronchial musculature.