title: Maternal weight gain rate in the second trimester are associated with birth weight and length of gestation.
abstract: BACKGROUND
  Low total weight gain during pregnancy has been widely accepted as a valid risk factor for small-for-gestational-age infants and pre-term births. However, it is not obvious in which trimester the weight gain rate most affects birth weight and length of gestation.
  
  
  METHODS
  Using logistic regression analysis and Pearson's correlation coefficient test, data from 472 women who had vaginally delivered an infant at term without any complications were analyzed retrospectively.
  
  
  RESULTS
  Pre-pregnancy underweight and low total maternal weight gain were significant independent predictors of small-for-gestational-age infants and shortened gestations. Pre-pregnancy weight was significantly related to the birth weight and length of gestation (r = 0.18, p < 0.0001; r = 0.10, p = 0.04, respectively), and total weight gain was also significantly related to those (r = 0.17, p = 0.0003; r = 0.11, p = 0.03, respectively). Significant correlations between maternal weight gain rate in the second trimester and the birth weight and length of gestation were found (r = 0.32, p = 0.005; r = 0.40, p = 0.0003, respectively), while such correlations were not found in the first or third trimester.
  
  
  CONCLUSIONS
  The most sensitive period of maternal weight gain for the birth weight and length of gestation was the second trimester.
authors.affiliation: School of Nursing, Faculty of Medicine, University of Oita, Oita, Japan.
authors.forename: Nobuko
authors.initials: N
authors.lastname: Sekiya
authors.forename: Takanobu
authors.initials: T
authors.lastname: Anai
authors.forename: Michiru
authors.initials: M
authors.lastname: Matsubara
authors.forename: Fumiko
authors.initials: F
authors.lastname: Miyazaki
mesh_terms: D000328:Adult; D001724:Birth Weight / Q000502:physiology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D011247:Pregnancy; D011256:Pregnancy Outcome; D011262:Pregnancy Trimester, Second / Q000502:physiology*; D015430:Weight Gain / Q000502:physiology*