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.