Influence of pregnancy on asthma exacerbation patterns: a UK population-based cohort

<bold>Background:</bold> GINA notes that during pregnancy, about one-third of women have worsening asthma symptoms, one-third improve, and one-third remain unchanged. This data is from a US cohort of 330 women from the 1980s. We wished to understand current exacerbation patterns. <bold>Methods:</bold> Using UK medical records, 2004-2019, we drew an asthma cohort with data: 1-year pre-pregnancy, during all 3 pregnancy trimesters, and 1-year post-pregnancy. We defined exacerbations as a short course of oral steroids or unplanned hospital visit. We calculated the proportion having ≥1 exacerbation in each 3-month period. <bold>Results:</bold> We included 72,791 pregnancies (mean age=31 years; mean pregnancy length=39 weeks). By asthma therapy in the year pre-pregnancy, 50% only used a reliever, 19% low-dose inhaled corticosteroids (ICS), 16% infrequent medium/high-dose ICS, 11% regular medium-dose ICS and 5% regular high-dose ICS. Overall, hospital-managed exacerbations rose in the second and third trimester. But primary care-managed exacerbations fell in all three trimesters (figure). All exacerbations were lower 3-months post-pregnancy. <bold>Conclusion:</bold> During pregnancy, there were relatively fewer primary care-managed exacerbations, especially if using higher doses of ICS, but more hospital and A&E admissions. All exacerbations fell 3-months post-pregnancy. By 12-months post-pregnancy, women using the highest ICS doses still had lower exacerbation rates than pre-pregnancy. <fig><object-id>erj;64/suppl_68/OA5577/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>