title: Maternal prepregnancy body mass index and gestational weight gain on pregnancy outcomes.
abstract: OBJECTIVE
  The aim of the present study was to evaluate the single and joint associations of maternal prepregnancy body mass index (BMI) and gestational weight gain (GWG) with pregnancy outcomes in Tianjin, China.
  
  
  METHODS
  Between June 2009 and May 2011, health care records of 33,973 pregnant women were collected and their children were measured for birth weight and birth length. The independent and joint associations of prepregnancy BMI and GWG based on the Institute of Medicine (IOM) guidelines with the risks of pregnancy and neonatal outcomes were examined by using Logistic Regression.
  
  
  RESULTS
  After adjustment for all confounding factors, maternal prepregnancy BMI was positively associated with risks of gestational diabetes mellitus (GDM), pregnancy-induced hypertension, caesarean delivery, preterm delivery, large-for-gestational age infant (LGA), and macrosomia, and inversely associated with risks of small-for-gestational age infant (SGA) and low birth weight. Maternal excessive GWG was associated with increased risks of pregnancy-induced hypertension, caesarean delivery, LGA, and macrosomia, and decreased risks of preterm delivery, SGA, and low birth weight. Maternal inadequate GWG was associated with increased risks of preterm delivery and SGA, and decreased risks of LGA and macrosomia, compared with maternal adequate GWG. Women with both prepregnancy obesity and excessive GWG had 2.2-5.9 folds higher risks of GDM, pregnancy-induced hypertension, caesarean delivery, LGA, and macrosomia compared with women with normal prepregnancy BMI and adequate GWG.
  
  
  CONCLUSIONS
  Maternal prepregnancy obesity and excessive GWG were associated with greater risks of pregnancy-induced hypertension, caesarean delivery, and greater infant size at birth. Health care providers should inform women to start the pregnancy with a BMI in the normal weight category and limit their GWG to the range specified for their prepregnancy BMI.
authors.affiliation: Tianjin Women's and Children's Health Center, Tianjin, China ; Chronic Disease Epidemiology Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America.
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.affiliation: Tianjin Women's and Children's Health Center, Tianjin, China.
authors.forename: Enqing
authors.initials: E
authors.lastname: Liu
authors.affiliation: Tianjin Women's and Children's Health Center, Tianjin, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Guo
authors.affiliation: Tianjin Women's and Children's Health Center, Tianjin, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Pan
authors.affiliation: Tianjin Women's and Children's Health Center, Tianjin, China.
authors.forename: Baojuan
authors.initials: B
authors.lastname: Li
authors.affiliation: Tianjin Women's and Children's Health Center, Tianjin, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.affiliation: Tianjin Women's and Children's Health Center, Tianjin, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Liu
authors.affiliation: Tianjin Women's and Children's Health Center, Tianjin, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Tianjin Women's and Children's Health Center, Tianjin, China.
authors.forename: Gongshu
authors.initials: G
authors.lastname: Liu
authors.affiliation: Departments of Epidemiology and Environmental Health, Harvard School of Public Health, Boston, Massachusetts, United States of America.
authors.forename: Andrea A
authors.initials: AA
authors.lastname: Baccarelli
authors.affiliation: Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America.
authors.forename: Lifang
authors.initials: L
authors.lastname: Hou
authors.affiliation: Chronic Disease Epidemiology Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America.
authors.forename: Gang
authors.initials: G
authors.lastname: Hu
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002681:China; D005260:Female; D006801:Humans; D016017:Odds Ratio; D011247:Pregnancy; D011256:Pregnancy Outcome; D015430:Weight Gain