How Pregnancy Affects Asthma in Korea: Risk Factors and Adherence Decline.

Abstract

Purpose: Pregnancy is a well-known trigger for asthma exacerbations, but risk prediction remains limited. This study aimed to evaluate the impact of pregnancy on asthma control, identify risk factors for exacerbations, and assess adherence to asthma management during and after pregnancy in Korea.

Methods: Women with asthma who gave birth between 2012 and 2015 in Korea were identified using the Korean National Health Insurance claims database. Asthma was defined as having at least three asthma diagnoses and at least one prescription of medication for asthma within 4 years before pregnancy. Asthma exacerbations during pregnancy were defined as the requirement for oral corticosteroid treatment or hospitalization, or an emergency department visit. A case-control study was conducted to evaluate risk factors for these exacerbations within the overall cohort and, specifically, among women who discontinued asthma medication during pregnancy. Postpartum adherence to asthma medication was also assessed.

Results: Among 123,355 women with asthma, 14.8% experienced asthma exacerbation during pregnancy, while 82.9% discontinued asthma medication during pregnancy. Long-term asthma control, spanning the 4 years before conception was more strongly associated with pregnancy outcomes than the 1-year assessment. During pregnancy, poor adherence to asthma treatment was strongly associated with exacerbations, and women who discontinued medication were particularly vulnerable if they had a history of pre-pregnancy exacerbations, moderate to severe rhinitis, multiple gestation, neuropsychiatric disorders, or prior inhaled corticosteroid use. Even after delivery, only 27.4% of asthmatics continued taking asthma medication.

Conclusions: This study emphasizes that long-term asthma control and medication maintenance throughout pregnancy are crucial for preventing exacerbations. High-risk women were characterized by comorbidities such as rhinitis, neuropsychiatric disorders, and multiple gestation. These findings underscore the importance of sustained asthma management and patient education not only before and during pregnancy but also throughout the postpartum period.