title: Associations of neonatal high birth weight with maternal pre-pregnancy body mass index and gestational weight gain: a case-control study in women from Chongqing, China.
abstract: To examine the associations of maternal pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) with neonatal high birth weight (HBW) in a sample of Chinese women living in southwest China.
  
  
  
  A hospital-based case-control study was conducted in Chongqing, China. A total of 221 mothers who delivered HBW babies (>4.0 kg) were recruited as cases and 221 age-matched (2-year interval) mothers with normal birth weight babies (2.5-4.0 kg) were identified as controls. ORs were estimated using conditional logistic regression analysis. For the analysis, pre-pregnancy BMI was categorised as underweight/normal weight/overweight and obesity and GWG was categorised as inadequate/appropriate/excessive.
  
  
  
  Among the cases, mean pre-pregnancy BMI was 21.8±2.8 kg/m(2), mean GWG was 19.7±5.1 kg and mean neonatal birth weight was 4.2±0.2 kg. In the controls, the corresponding values were 21.1±3.1 kg/m(2), 16.4±5.0 kg and 3.3±0.4 kg, respectively. More cases than controls gained excessive weight during pregnancy (80.1% vs 48.4%, p<0.001). No significant association was found between pre-pregnancy BMI and HBW babies (OR=1.04, 95% CI 0.97 to 1.11; p>0.05). GWG was positively related to HBW after adjustment for gravidity, gestational age, newborns' gender and family income (OR=1.18, 95% CI 1.12 to 1.25; p<0.001). The adjusted OR of delivering HBW babies was 5.39 (95% CI 2.94 to 9.89; p<0.001) for excessive GWG versus appropriate GWG. This OR was strengthened among pre-pregnancy normal weight women (OR=10.27, 95% CI 3.20 to 32.95; p<0.001).
  
  
  
  Overall, the findings suggest a significantly positive association between GWG and HBW. However, pre-pregnancy BMI shows no independent relationship with HBW.
authors.affiliation: College of Public Health and Management, Chongqing Medical University, Chongqing, China School of Nursing, The Hong Kong Polytechnic University, Hong Kong, Hong Kong.
authors.forename: Yao Jie
authors.identifier: 0000-0001-9289-4985
authors.initials: YJ
authors.lastname: Xie
authors.affiliation: College of Public Health and Management, Chongqing Medical University, Chongqing, China Affiliated Hospital of Chengdu University, Chengdu, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Peng
authors.affiliation: College of Public Health and Management, Chongqing Medical University, Chongqing, China.
authors.forename: Lingli
authors.initials: L
authors.lastname: Han
authors.affiliation: The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Zhou
authors.affiliation: The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Zhengai
authors.initials: Z
authors.lastname: Xiong
authors.affiliation: Chongqing Maternal and Child Health Care Hospital, Chongqing, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: The First Affiliated Hospital of the Third Military Medical University, Chongqing, China.
authors.forename: Junnan
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Nutritional Sciences, University of Cincinnati, Cincinnati, USA.
authors.forename: Ruoxue
authors.initials: R
authors.lastname: Yao
authors.affiliation: Children's Nutrition Research Centre, Key Laboratory of Developmental Diseases in Childhood of Education Ministry, Children's Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Tingyu
authors.initials: T
authors.lastname: Li
authors.affiliation: College of Public Health and Management, Chongqing Medical University, Chongqing, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000328:Adult; D001724:Birth Weight; D015992:Body Mass Index; D016022:Case-Control Studies; D002681:China; D005260:Female; D005320:Fetal Macrosomia / Q000453:epidemiology*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D009765:Obesity / Q000453:epidemiology*; D016017:Odds Ratio; D050177:Overweight / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology*; D013851:Thinness / Q000453:epidemiology*; D015430:Weight Gain; D055815:Young Adult
keywords: birth weight; body mass index; case-control study; gestational weight gain; macrosomia; pregnancy