title: The impact of change in pregnancy body mass index on the development of gestational hypertensive disorders.
abstract: OBJECTIVE
  To examine the impact of change in body mass index (BMI) during pregnancy on the incidence of gestational hypertension/preeclampsia.
  
  
  METHODS
  This is a retrospective cohort study using linked California birth certificate and discharge diagnosis data from the year 2007. Adjusted odds ratios (aOR) and 95% confidence intervals (CI) were calculated for the outcome of gestational hypertension/preeclampsia, as a function of a categorical change in pregnancy BMI: BMI loss (<-0.5), no change (-0.5 to 0.5), minimal (0.6 to 5), moderate (5.1 to 10) and excessive (>10). The impact of change in pregnancy BMI was evaluated for the entire cohort and then as a function of prepregnancy BMI category. Women with no change in pregnancy BMI served as the reference group.
  
  
  RESULTS
  The study population consisted of 436 414 women with singleton gestations. Overall, women with excessive BMI change had a nearly twofold increased odds of gestational hypertension/preeclampsia (aOR=1.94; 95% CI=1.72 to 2.20). By prepregnancy BMI class, overweight and obese women who had a moderate change in pregnancy BMI also had increased odds of developing gestational hypertension/preeclampsia with aOR ranging from 1.73 to 1.97.
  
  
  CONCLUSIONS
  Regardless of prepregnancy BMI category, women with excessive BMI change have a higher chance of developing gestational hypertension/preeclampsia. Overweight and obese women with moderate BMI change may also be at increased risk.
authors.affiliation: Department of Obstetrics and Gynecology, University of California Irvine Medical Center, Orange, CA, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Swank
authors.affiliation: Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR, USA.
authors.forename: A B
authors.initials: AB
authors.lastname: Caughey
authors.affiliation: Department of Obstetrics and Gynecology, University of California Irvine Medical Center, Orange, CA, USA.
authors.forename: C K
authors.initials: CK
authors.lastname: Farinelli
authors.affiliation: California Maternal Quality Care Collaborative (CMQCC), Stanford, CA, USA.
authors.forename: E K
authors.initials: EK
authors.lastname: Main
authors.affiliation: California Maternal Quality Care Collaborative (CMQCC), Stanford, CA, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Melsop
authors.affiliation: Department of Obstetrics and Gynecology, Sutter Medical Center, Sacramento, Sacramento, CA, USA.
authors.forename: W M
authors.initials: WM
authors.lastname: Gilbert
authors.affiliation: Department of Obstetrics and Gynecology, University of California Irvine Medical Center, Orange, CA, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Chung
mesh_terms: D000328:Adult; D015992:Body Mass Index; D005260:Female; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000209:etiology*; D016017:Odds Ratio; D011225:Pre-Eclampsia / Q000209:etiology; D011247:Pregnancy; D012189:Retrospective Studies; D015430:Weight Gain