Antenatal characteristics according to pre-pregnancy body mass index.

Note: BMI = Body mass index; SD = Standard deviation
* Unless stated otherwise
†p value indicates statistical difference between each BMI category and reference category for the related characteristic
a At the beginning of actual pregnancy
b During actual pregnancy
c Refers to a previous history of illness or surgery to breast
d Number of months of breastfeeding experimented by women with one or more previous children. Refer exclusively to multiparous women (n = 3451)
Antenatal characteristics according to pre-pregnancy body mass index.