Association between categories of smoking during pregnancy (SPD) and offspring's birthweight by different designs.

All models were adjusted for gestational age, marital status, maternal age, birth order, sex of the newborn, complications during pregnancy (i.e., diabetes, hypertension and urinary problems), and Swedish snus use.所有模型均已针对胎龄、婚姻状况、母亲年龄、出生胎次、新生儿性别、妊娠并发症（即糖尿病、高血压及泌尿系统疾病）以及瑞典鼻烟（snus）使用情况进行校正。