The positive associations of maternal higher prepregnancy BMI
and excessive GWG with the risk of larger birth weight of infants
were similar to previous studies [3,11,33]. A clear association exists
between maternal obesity and infant size at birth. In recent years
researchers have recognized that excessive GWG is also associated
with increased weight at birth [3]. In the present study, maternal
excessive GWG had a 2.32 fold risk of infant LGA compared with
those women with adequate GWG. Similarly, mothers with
prepregnancy overweight or obesity had a 1.73–2.80 fold risk of
infant LGA compared with those mothers with normal prepregnancy
weight. A recent study reported that the greatest difference
in neonatal fat mass was observed among prepregnancy
overweight women with excessive GWG compared with overweight
women with adequate GWG [34]. For women within the excessive GWG category, infants born to normal weight mothers
had lower percent body fat (11.8%) than infants born to
overweight mothers (13.7%) and obese mothers (14.2%). Infants
born to mothers with excessive GWG had greater fat-free mass
than infants born to mothers with adequate GWG [34]. This
indicated that maternal excessive GWG might play an important
role as prepregnancy BMI in the offspring’s overweight, and might
contribute to the overweight epidemic among infants and children.
One important issue of reverse causality should be also considered
in the analyses of maternal GWG with infant LGA. It has been
suggested that associations of maternal GWG with infant LGA do
not result from GWG itself, but rather to underlying factors that
influence both weight gain and the outcomes, such as maternal
diet composition and physical activity level. In addition, it is
important to determine whether these relationships are independent
of prepregnancy BMI or if they differ by prepregnancy BMI.
The present study indicated that the positive association of
maternal GWG and the risk of infant LGA was consistent among
women different prepregnancy BMI and independent of maternal
prepregnancy BMI