title: Maternal Prepregnancy Body Mass Index and Small for Gestational Age Births in Chinese Women.
abstract: Both high and low prepregnancy body mass index (BMI) has been associated with small for gestational age births (SGA; birthweight below the population specific 10th centile for the gestational age), but results remain inconsistent. We examined the association between maternal BMI and SGA, and evaluated if the associations were modified by preterm birth (being born prior to 37 weeks) status.
  
  
  
  A population-based cohort study was conducted in Wuhan, China from June 2011, to June 2013. Women who delivered a non-malformed livebirth (n = 76 695) were included using the Wuhan Maternal and Child Health Management Information System. Log-binomial regression models were used to analyse the associations between prepregnancy BMI, categorized using thresholds adapted to the Chinese population, and SGA. Stratified analyses were used to examine the relationship of prepregnancy BMI to preterm-SGA and term-SGA.
  
  
  
  Of the 76 695 live births, 3058 (4.0%) were delivered preterm. For babies born at term, prepregnancy underweight (<18.5 kg/m2) was associated with an increased risk of SGA, the adjusted risk ratio (RR) was 1.41 (95% confidence interval (CI) 1.33, 1.49), whereas, being overweight (24.0-27.9 kg/m2) was associated with a decreased risk (RR 0.84, 95% CI 0.74, 0.94). For babies born preterm, prepregnancy underweight was not associated with risk of SGA, but being overweight was associated with an increased risk (RR 1.57, 95% CI 1.04, 2.35).
  
  
  
  These data suggest that the association of overweight and underweight prepregnancy BMI and SGA differs depending on whether the baby is full term or preterm.
authors: Wuhan Medical and Health Center for Women and Children, Wuhan, China.
authors: Bin
authors: B
authors: Zhang
authors: Wuhan Medical and Health Center for Women and Children, Wuhan, China.
authors: Shaoping
authors: S
authors: Yang
authors: Wuhan Medical and Health Center for Women and Children, Wuhan, China.
authors: Rong
authors: R
authors: Yang
authors: College for Public Health and Social Justice, Saint Louis University, Saint Louis, MO.
authors: Jing
authors: J
authors: Wang
authors: Wuhan Environmental Monitoring Center, Wuhan, China.
authors: Shengwen
authors: S
authors: Liang
authors: Wuhan Medical and Health Center for Women and Children, Wuhan, China.
authors: Ronghua
authors: R
authors: Hu
authors: College for Public Health and Social Justice, Saint Louis University, Saint Louis, MO.
authors: Hong
authors: H
authors: Xian
authors: Wuhan Environmental Monitoring Center, Wuhan, China.
authors: Ke
authors: K
authors: Hu
authors: Wuhan Medical and Health Center for Women and Children, Wuhan, China.
authors: Yimin
authors: Y
authors: Zhang
authors: College for Public Health and Social Justice, Saint Louis University, Saint Louis, MO.
authors: Nancy L
authors: NL
authors: Weaver
authors: Wuhan Environmental Monitoring Center, Wuhan, China.
authors: Hongming
authors: H
authors: Wei
authors: College for Public Health and Social Justice, Saint Louis University, Saint Louis, MO.
authors: Michael G
authors: MG
authors: Vaughn
authors: Wuhan Environmental Monitoring Center, Wuhan, China.
authors: Hui
authors: H
authors: Peng
authors: College for Public Health and Social Justice, Saint Louis University, Saint Louis, MO.
authors: Brian B
authors: BB
authors: Boutwell
authors: Wuhan Environmental Monitoring Center, Wuhan, China.
authors: Zhen
authors: Z
authors: Huang
authors: College for Public Health and Social Justice, Saint Louis University, Saint Louis, MO.
authors: Zhengmin
authors: Z
authors: Qian
mesh_terms: D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D002681:China / Q000208:ethnology; D004522:Educational Status; D004651:Employment / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007234:Infant, Premature / Q000502:physiology*; D007236:Infant, Small for Gestational Age / Q000502:physiology*; D008297:Male; D050177:Overweight / Q000208:ethnology*; D016742:Preconception Care; D011247:Pregnancy; D011248:Pregnancy Complications / Q000208:ethnology*; D047928:Premature Birth / Q000208:ethnology; D012307:Risk Factors; D012621:Seasons; D047929:Term Birth / Q000502:physiology; D013851:Thinness / Q000208:ethnology*; D055815:Young Adult
keywords: pre-pregnant body mass index; preterm birth; small for gestational age