OBJECTIVETo examine the effect of maternal pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) with childhood overweight and adiposity, and to explore possible early life risk factors for obesity in preschool children.

METHODSBasic information of pregnant women and gestation period came from the Ma'anshan Birth Cohort Study, a part of the China-Anhui Birth Cohort Study (C-ABCS). Pregnant women in routine health care from four municipal medical and health institutions were enrolled voluntarily during October 2008 and October 2010 in Ma'anshan City. A total of 5 084 pregnant women and 4 669 singleton live births were included in this study. Between April 2014 and April 2015, 3 797 children were followed up. Children whose BMI were >85th percentiles for age and genders of World Health Organization (WHO) reference were considered as overweight, and >95th percentiles for age and genders cut-off values were considered as obesity (pathological and secondary causes of obesity were excluded). Gestational weight gain was defined according to the Institute of Medicine (IOM) guidelines. Univariate and binary regression model analysis was used to examine the effect of pre-pregnancy BMI and GWG with childhood overweight and adiposity.

RESULTSOf the 3 797 pregnant women, the prevalence of underweight, normal weight, overweight and obesity were respectively 22.6% (n=858), 70.3% (n=2 671), 6.2% (n=234) and 0.9% (n=34). There were 3 563 pregnant women who were obtained gestational weight gain data, the prevalence of inadequate GWG, appropriate GWG, excessive GWG were respectively 12.4% (n=443), 25.9% (n=922) and 61.7% (n=2 198). The prevalence of overweight and obesity were 11.5% (n=437) and 10.8% (n= 411) in preschool children, respectively. After adjusting confounding factors including age at delivery, genders of children, children age, birth weight, breastfeeding and household economic status, binary logistic regression analysis showed that pre-pregnancy overweight and obesity(OR=2.01, 95% CI: 1.53-2.65), excessive GWG(OR=1.65, 95% CI: 1.35-2.03) were risk factors for overweight and obesity, and pre-pregnancy underweight was protective factor for childhood overweight and obesity (OR=0.49, 95% CI: 0.39-0.62). Joint associations of pre-pregnancy BMI and inappropriate GWG were also noticed in the study: compared to only pre-pregnancy higher BMI or excessive GWG or indequate GWG, combination of high pre-pregnancy BMI and excessive GWG or high pre-pregnancy BMI and inadequate GWG, adverse effects on childhood overweight and obesity were much higher,OR (95%CI) values were 2.90(1.97-4.28), 3.17(1.44-6.97) respectively.

CONCLUSIONBoth high pre-pregnancy BMI and inappropriate GWG are associated with greater offspring BMI. Pregnant women should achieve appropriate weight gain and help prevent obesity in their children.