Associations between tobacco smoking during pregnancy and offspring asthma have been observed, but the role of nicotine and familial factors remains unclear.

中文翻译：

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怀孕期间吸烟和使用鼻烟以及学龄前儿童患哮喘和喘息的风险——一项基于人群的登记研究

已经观察到怀孕期间吸烟与后代哮喘之间的关联，但尼古丁和家族因素的作用仍不清楚。