[Influence of pre-pregnancy parental body mass index, maternal weight gain during pregnancy, and their interaction on neonatal birth weight].

Objective: To investigate the influence of pre-pregnancy parental body mass index (BMI), maternal weight gain during pregnancy, and their interaction on neonatal birth weight.

Methods: A total of 1 127 pregnant women who underwent regular prenatal examinations and full-term singleton delivery in the First Hospital of Xi'an Jiaotong University from January 2017 to October 2018 were enrolled. The data on their pre-pregnancy BMI, maternal weight gain during pregnancy, pre-pregnancy BMI of the husband, and neonatal birth weight were collected. The interaction between pre-pregnancy parental BMI and maternal weight gain during pregnancy was analyzed, and their correlation with neonatal birth weight was analyzed.

Results: Among the 1 127 full-term neonates, the detection rates of low birth weight neonates and macrosomia were 2.22% (25/1 127) and 3.82% (43/1 127) respectively. There were significant differences in pre-pregnancy parental BMI and maternal weight gain during pregnancy among the low birth weight, normal birth weight, and macrosomia groups (P<0.05). Neonatal birth weight was positively correlated with pre-pregnancy parental BMI and maternal weight gain during pregnancy (r=0.097-0.322, P<0.05). Low maternal weight before pregnancy increased the risk of low birth weight (RR=4.17, 95%CI: 1.86-9.38), and maternal overweight/obesity before pregnancy (RR=3.59, 95%CI: 1.93-6.67) and excessive weight gain during pregnancy (RR=3.21, 95%CI: 1.39-7.37) increased the risk of macrosomia. No interaction between pre-pregnancy maternal BMI and maternal weight gain during pregnancy was observed.

Conclusions: Pre-pregnancy parental BMI and maternal weight gain during pregnancy are related to neonatal birth weight, and there is no interaction between pre-pregnancy maternal BMI and maternal weight gain during pregnancy.