Asthma exacerbation (AE) is a significant clinical problem during pregnancy. This study aimed to identify factors and perinatal and offspring outcomes associated with AE during pregnancy. We conducted a retrospective cohort study using the Peking University Third Hospital database from January 1, 2013 to December 31, 2020. We compared the clinical characteristics and perinatal and offspring outcomes of asthma with and without exacerbations among women who delivered during this period. The prevalence of gestational asthma increased from 0.52% in 2013 to 0.98% in 2020. Of the 220 patients with gestational asthma included in the study, 105 experienced AE during pregnancy: 62.9% (n = 66) had mild-to-moderate AE and 37.1% (n = 39) had severe AE. Pregnant women with allergic rhinitis have a higher risk of AE during pregnancy. The mean fetal weight was lower in the AE group than in the non-AE group (p = 0.01). Women who experienced AE were more at risk for gestational hypertension and preeclampsia than women who did not experience any exacerbation.