Asthma is common among pregnant women, and the incidence of asthma exacerbations during pregnancy is high. This literature review provides an overview of the impact of exacerbations of asthma during pregnancy on pregnancy-related complications. The majority of published retrospective studies reveal that asthma exacerbations during pregnancy increase the risk of pre-eclampsia, gestational diabetes, placental abruption and placenta praevia. Furthermore, these women also have higher risk for breech presentation, haemorrhage, pulmonary embolism, caesarean delivery, maternal admission to the intensive care unit and longer postpartum hospital stay. Asthma has been associated with increased risk of intrauterine growth retardation, small-for-gestational age, low birth weight, infant hypoglycaemia and preterm birth, but more recent prospective studies have not revealed significant associations with regard to these outcomes. In conclusion, asthma exacerbations during pregnancy are associated with complications of pregnancy, labour and delivery. Prevention of exacerbations is essential to reduce the risk of complications and poor outcome.