ABSTRACT
Breathlessness in pregnancy is usually due to physiological changes and less commonly to other conditions. The incidence of these conditions in pregnancy is difficult to estimate owing to a lack of relevant studies. Breathlessness, which is the sensation of difficulty in breathing, should be distinguished from tachypnoea, which is an increased respiratory rate. Physiological breathlessness usually starts in the first or second trimester and increases in incidence as gestation progresses. Nasal obstruction due to rhinitis may occur in up to 30 per cent of pregnant women, as a result of mucosal oedema, hyperaemia, capillary congestion, and mucus hypersecretion, which are caused by increased oestrogen levels. This occurs mostly in the third trimester and may lead to a sensation of breathlessness, particularly if severe. Asthma is by far the most common obstructive airways disease likely to be encountered in pregnancy, occurring in 0.4–7 per cent of women.
