Asthma and Pregnancy: Possible to prevent complications?- With Special reference to the impact of obesity and type of airwayinflammation

Background Asthma is a serious global health issue and the most prevalent chronic disorder among Danish pregnant women. Exacerbations of asthma during pregnancy have been associated with increased risk of adverse pregnancy and perinatal outcomes, and by that making asthma a potential serious medical condition during pregnancy. Monitoring of asthma every four to six weeks is recommended during pregnancy, although evidence is lacking that following this recommendation will improve pregnancy outcome and, not least, be beneficial for all pregnant women with asthma. Aim The overall aim of the present thesis was to gain more knowledge of the interaction between asthma and pregnancy. The specific research questions were to identify pregnancies with low risk of an exacerbation during pregnancy, to identify risk factors for an exacerbation during pregnancy, and to compare the adverse pregnancy and perinatal outcomes in women without asthma and women with asthma monitored closely as recommended during pregnancy. Methods In study I and II, determinants of pregnancies with low risk of an exacerbation and maternal pregnancy-related risk factors for an exacerbations were investigated in a large prospective cohort study with 1.283 women with asthma. The Management of Asthma during Pregnancy (MAP) was initiated in 2007, and all pregnant women referred to Hvidovre Hospital have since then received an invitation to participate. Women were followed-up every four weeks with assessment of asthma control and adjustment of medication if necessary. In study III, the potential differences in airway hyperresponsiveness and airway inflammation, in participants (n=50) from the MAP cohort, were investigated in a post-partum examination. In study IV, the effect of maternal asthma on obstetrical and perinatal outcomes was investigated in a large case-control study, with 938 cases i.e. women with asthma from the MAP cohort, and 2.778 controls i.e. women without asthma. Results No history of pre-pregnancy exacerbations, no prescribed controller medication, and clinically stable asthma at the first visit was determinants of pregnancies with a low risk of an asthma exacerbation during pregnancy (study I). Excessive gestational weight gain (GWG) in first trimester was associated with increased risk of an asthma exacerbation during pregnancy; furthermore, the impact of GWG was dose-dependent (Study II). In study III, women experiencing an asthma exacerbation during pregnancy had more pronounced airway hyperresponsiveness and were more often non-atopic. Finally, in study IV, the overall risk of adverse obstetrical and perinatal outcomes in women with asthma monitored closely during pregnancy was low. Conclusion Women with no history of pre-pregnancy exacerbations, no prescribed controller medication, and clinically stable asthma at the first visit have a very low risk of an exacerbation. Furthermore, excessive GWG, airway hyperresponsiveness and being non-atopic are risk factors for exacerbations of asthma during pregnancy. However, the overall risk of adverse obstetrical and perinatal outcomes in women with actively managed asthma during pregnancy is comparable to women without asthma