title: Correlation between birth weight and maternal body composition.
abstract: OBJECTIVE
  To estimate which maternal body composition parameters measured using multifrequency segmental bioelectric impedance analysis in the first trimester of pregnancy are predictors of increased birth weight.
  
  
  METHODS
  Nondiabetic women were recruited after ultrasonographic confirmation of an ongoing singleton pregnancy in the first trimester. Maternal body composition was measured using bioelectric impedance analysis. Multivariable linear regression analysis was performed to identify the strongest predictors of birth weight, with multiple logistic regression analysis performed to assess predictors of birth weight greater than 4 kg.
  
  
  RESULTS
  Data were analyzed for 2,618 women, of whom 49.6% (n=1,075) were primigravid and 16.5% (n=432) were obese based on a body mass index (BMI) of 30 or higher. In univariable analysis, maternal age, BMI, parity, gestational age at delivery, smoking, fat mass, and fat-free mass all correlated significantly with birth weight. In multivariable regression analysis, fat-free mass remained a significant predictor of birth weight (model R=0.254, standardized β=0.237; P<.001), but no relationship was found between maternal fat mass and birth weight. After adjustment for confounding variables, women in the highest fat-free mass quartile had an adjusted odds ratio of 3.64 (95% confidence interval 2.34-5.68) for a birth weight more than 4 kg compared with those in the lowest quartile.
  
  
  CONCLUSIONS
  Based on direct measurements of body composition, birth weight correlated positively with maternal fat-free mass and not adiposity. These findings suggest that, in nondiabetic women, interventions intended to reduce fat mass during pregnancy may not prevent large-for-gestational-age neonates and revised guidelines for gestational weight gain in obese women may not prevent large-for-gestational-age neonates.
  
  
  METHODS
  : III.
authors.affiliation: UCD Centre for Human Reproduction, Coombe Women and Infants University Hospital, Dublin, Ireland. ekent@rcsi.ie
authors.forename: Etaoin
authors.initials: E
authors.lastname: Kent
authors.forename: Vicky
authors.initials: V
authors.lastname: O'Dwyer
authors.forename: Chro
authors.initials: C
authors.lastname: Fattah
authors.forename: Nadine
authors.initials: N
authors.lastname: Farah
authors.forename: Clare
authors.initials: C
authors.lastname: O'Connor
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Turner
mesh_terms: D000293:Adolescent; D000328:Adult; D001724:Birth Weight; D001823:Body Composition; D015992:Body Mass Index; D017097:Electric Impedance; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D008423:Maternal Age; D009765:Obesity / Q000150:complications; D011247:Pregnancy; D016216:Ultrasonography, Prenatal; D055815:Young Adult