Asthma is present in 4-7% of pregnant women. The course of asthma during pregnancy varies, a third remaining stable, another third improving and the rest getting worse. Asthmatic women have an increased risk of gestational arterial hypertension, preeclampsia, gravidarum hyperemesis, placenta previa, vaginal haemorrhage and induced and/or complicated childbirth. Objective: this work was aimed at reviewing the epidemiology, clinical classification, diagnosis and treatment of asthma during pregnancy. Materials and methods: using the key words described in the second sentence in the Introduction to search for information in PUBMED/Medline, Cochrane, SciELO databases, as well as in articles in journals and texts, mainly covering the last 5 years. Search results gave 84 references of which the 39 most relevant were taken. Results: good control of asthma during pregnancy avoids or reduces maternal and foetal complications. Conclusion: better control of pulmonary function during pregnancy is independently associated with increased foetal growth.