title: Composition of gestational weight gain impacts maternal fat retention and infant birth weight.
abstract: OBJECTIVE
  The purpose of this study was to evaluate how changes in gestational weight and body composition affect infant birth weight and maternal fat retention after delivery in underweight, normal-weight and overweight women.
  
  
  METHODS
  We assessed the body composition of 63 women (low body mass index, 17 women; normal body mass index, 34 women; and high body mass index, 12 women) on the basis of measurements of total body nitrogen by prompt-gamma activation analysis, total body potassium by whole body counting, and a multicomponent model based on total body water by deuterium dilution, body volume by densitometry, and bone mineral content by dual energy x-ray absorptiometry (DXA) before pregnancy, at 9, 22, and 36 weeks of gestation, and at 2, 6, and 27 weeks after delivery. Infant weight and length were recorded at birth; infant anthropometry and body composition by DXA were assessed at 2 and 27 weeks of age.
  
  
  RESULTS
  Gestational weight gain was correlated significantly with gains in total body water, total body potassium, protein, fat-free mass, and fat mass (P=.001-.003). Gains in total body water, total body potassium, protein and fat-free mass did not differ among body mass index groups; however, fat mass gain was higher in the high body mass index group (P=.03). Birth weight was correlated positively with gain in total body water, total body potassium, and fat-free mass (P<.01), but not fat mass. Postpartum weight and fat retention were correlated positively with gestational weight gain (P=.001) and fat mass gain (P=.001) but not with total body water, total body potassium, or fat-free mass gain.
  
  
  CONCLUSIONS
  Appropriate, but not excessive, gestational weight gain is needed to optimize infant birth weight and minimize maternal postpartum fat retention.
authors.affiliation: U.S. Department of Agriculture/Agriculture Research Service, Children's Nutrition Research Center, 1100 Bates Street, Houston, TX 77030, USA. nbutte@bcm.tmc.edu
authors.forename: Nancy F
authors.initials: NF
authors.lastname: Butte
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Ellis
authors.forename: William W
authors.initials: WW
authors.lastname: Wong
authors.forename: Judy M
authors.initials: JM
authors.lastname: Hopkinson
authors.forename: E O'Brian
authors.initials: EO
authors.lastname: Smith
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology*; D000328:Adult; D000886:Anthropometry; D001724:Birth Weight; D001823:Body Composition; D001835:Body Weight; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D049590:Postpartum Period; D011247:Pregnancy / Q000502:physiology*; D015430:Weight Gain