title: The impact of interpregnancy weight change on birthweight in obese women.
abstract: OBJECTIVE
  The purpose of this study was to estimate the impact of interpregnancy weight change from first to second pregnancies in obese women on the risk of large-for-gestational-age (LGA) and small-for-gestational-age (SGA) infants.
  
  
  METHODS
  A population-based historical cohort analysis of 10,444 obese women in Missouri who delivered their first 2 singleton live infants from 1998-2005. Interpregnancy weight change was calculated as the difference between prepregnancy body mass index (BMI) of the first and second pregnancies. LGA and SGA births were compared among 3 interpregnancy weight change groups: (1) weight loss (≥2 BMI units), (2) weight gain (≥2 BMI units), and (3) reference group (BMI maintained within 2 units). Adjusted odds ratios (aOR) were calculated for LGA and SGA births with the use of multiple logistic regression. A dose-response relationship was assessed with a linear-by-linear χ(2) test.
  
  
  RESULTS
  Compared with the reference group, interpregnancy weight loss was associated with lower risk of an LGA infant (aOR, 0.61; 95% confidence interval, 0.52-0.73), whereas interpregnancy weight gain was associated with increased risk of an LGA infant (aOR, 1.37; 95% confidence interval, 1.21-1.54). Interpregnancy BMI change was not related to SGA infant risk, except for weight loss of >8 BMI units. A significant dose-response relationship was observed for LGA infant risk (P < .001), but not SGA infant risk (P = .840).
  
  
  CONCLUSIONS
  Mild-to-moderate interpregnancy weight loss in obese women reduced the risk of subsequent birth of LGA infants without increasing the risk of SGA infants. The interpregnancy interval may be a crucial period for targeting weight loss in obese women.
authors.affiliation: Department of Obstetrics, Gynecology, and Women's Health, Saint Louis University School of Medicine, St. Louis, MO, USA.
authors.forename: Arun P
authors.initials: AP
authors.lastname: Jain
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Gavard
authors.forename: Jim J
authors.initials: JJ
authors.lastname: Rice
authors.forename: Rosemary B
authors.initials: RB
authors.lastname: Catanzaro
authors.forename: Raul
authors.initials: R
authors.lastname: Artal
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Hopkins
mesh_terms: D000328:Adult; D001724:Birth Weight / Q000502:physiology*; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D009765:Obesity / Q000503:physiopathology*; D011247:Pregnancy; D012307:Risk Factors; D015430:Weight Gain / Q000502:physiology*; D015431:Weight Loss / Q000502:physiology*