title: Factors associated with the pattern of maternal weight gain during pregnancy.
abstract: OBJECTIVE
  To examine the pattern of maternal weight gain using maternal characteristics and pregnancy outcome.
  
  
  METHODS
  We used maternal weight data measured prospectively from all deliveries between 1980-1990 at the University of California, San Francisco. Piecewise linear regression was used to estimate the rate of maternal weight gain in each trimester. Bivariate techniques were used to examine associations between maternal weight gain per trimester and maternal characteristics and pregnancy outcomes. We also used multiple regression analysis to examine the relationship between maternal characteristics and trimester weight gain.
  
  
  RESULTS
  Weight data for at least one trimester were available for 10,418 women. The average rate of weight gain (kg/week) was lowest during the first trimester (0.169 +/- 0.268, n = 7587), peaked during the second trimester (0.563 +/- 0.236, n = 8000), and slowed slightly in the third trimester (0.518 +/- 0.234, n = 10,052). Maternal height, hypertension, cesarean delivery, and fetal size correlated positively with the rate of gain in each trimester, but pre-pregnancy body size, age, parity, smoking status, race-ethnicity, and diabetes were associated differently with gain, depending on which trimester was examined. The most important maternal predictors of weight gain per trimester were age and Asian race-ethnicity in the first trimester; pre-pregnancy body mass, parity, and height in the second; and hypertension, age, and parity in the third.
  
  
  CONCLUSIONS
  Maternal weight gain per trimester is associated with a number of maternal characteristics and pregnancy outcomes, and these relationships vary according to which trimester is being examined.
authors.affiliation: Division of Public Health Biology and Epidemiology, School of Public Health, University of California, Berkeley, USA.
authors.forename: B
authors.initials: B
authors.lastname: Abrams
authors.forename: S
authors.initials: S
authors.lastname: Carmichael
authors.forename: S
authors.initials: S
authors.lastname: Selvin
mesh_terms: D000328:Adult; D001724:Birth Weight; D015992:Body Mass Index; D036861:Delivery, Obstetric; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D016014:Linear Models; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy / Q000208:ethnology / Q000502:physiology*; D011248:Pregnancy Complications / Q000453:epidemiology; D011256:Pregnancy Outcome / Q000453:epidemiology*; D012044:Regression Analysis; D012907:Smoking / Q000453:epidemiology; D015430:Weight Gain / Q000502:physiology*