Mehtods Body height and body weight of different gestation periods were measured on 280 uniparous pregnant women with singleton birth,and BMI was calculated.

• 方法:通过测量280例单胎初产妇的身高和妊娠各期的体重,计算体重指数(BMI),并将分娩正常体重新生儿的孕妇孕期体重指数与分娩低体重儿和巨大儿的孕妇进行比较。