Improvements of maternal, fetal, and child health are key public
health goals. In recent years, maternal prepregnancy body mass
index (BMI) has increased among the childbearing age women in
developed countries [1]. It has been shown that women who are
overweight or obese at the start of pregnancy are at increased risks
of poor maternal and child health outcomes. Several recent studies
reported that prepregnancy BMI was positively associated with
infant birth weight [2,3]. Furthermore, women who gain weight
excessively or inadequately during pregnancy are at increased risks
of poor maternal and child health outcomes [4–6]. Weight gain
during pregnancy within the recommended range (11 to 40
pounds) remained constant during the last 10 years [7]. Several
studies have shown that maternal excessive gestational weight gain
(GWG) was associated with increased risks of pregnancy-induced
hypertension, gestational diabetes mellitus (GDM), caesarean
delivery and large for gestational age infant, and maternal
inadequate GWG was associated with increased risks of low birth
weight and small for gestational age infant [4–6]. The Danish
National Birth Cohort found that excessive GWG increased risks
of caesarean delivery and large for gestational age infant, and
inadequate GWG increased the risk of having a small baby [3].