Background characteristics of study population of 284 214 pregnancies by asthma status.

*Asthma recorded in the Swedish Medical Birth Register, asthma diagnosis in the Swedish National Patient Register and/or asthma medication suspended at least twice according to the Swedish Prescribed Drug Register.

* 哮喘的判定标准如下：在瑞典医学出生登记册（Swedish Medical Birth Register）中有相关记录，或在瑞典国家患者登记册（Swedish National Patient Register）中确诊哮喘，亦或是依据瑞典处方药物登记册（Swedish Prescribed Drug Register）显示患者至少两次停用哮喘药物。