title: Prepregnancy body mass index in a first uncomplicated pregnancy and outcomes of a second pregnancy.
abstract: OBJECTIVE
  This study examined the effect of body mass index (BMI) before a first uncomplicated pregnancy on maternal and fetal outcomes in a subsequent pregnancy, including preterm births, preeclampsia, cesarean delivery, small for gestational age, large for gestational age, and neonatal deaths.
  
  
  METHODS
  We conducted a population-based cohort study (n = 121,092) using the Missouri maternally linked birth registry (1989 through 2005). Multivariable binary logistic regression models were fit to estimate odds ratios and 95% confidence intervals for the parameters of interest after controlling for sociodemographic and pregnancy-related confounders in the second pregnancy.
  
  
  RESULTS
  Compared to women with a normal BMI in their first pregnancy, those who were underweight prepregnancy had increased odds for preterm birth by 20% and small for gestational age by 40% in their second pregnancy, while those with prepregnancy obesity had increased odds for large for gestational age, preeclampsia, cesarean delivery, and neonatal deaths in their second pregnancy by 54%, 156%, 85%, and 37%, respectively.
  
  
  CONCLUSIONS
  Women starting a first pregnancy with suboptimal BMI may be at risk of adverse maternal and fetal outcomes in a subsequent pregnancy, even if their first pregnancy was uncomplicated or if they reached a normal weight by their second pregnancy. The long-term consequences of suboptimal BMI carry considerable public health implications.
authors.affiliation: Department of Epidemiology, College for Public Health and Social Justice, Saint Louis University, St. Louis, MO. Electronic address: mtabet@slu.edu.
authors.forename: Maya
authors.initials: M
authors.lastname: Tabet
authors.affiliation: Department of Epidemiology, College for Public Health and Social Justice, Saint Louis University, St. Louis, MO.
authors.forename: Louise H
authors.initials: LH
authors.lastname: Flick
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, School of Medicine, Washington University in St. Louis, St. Louis, MO.
authors.forename: Methodius G
authors.initials: MG
authors.lastname: Tuuli
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, School of Medicine, Washington University in St. Louis, St. Louis, MO.
authors.forename: George A
authors.initials: GA
authors.lastname: Macones
authors.affiliation: Department of Epidemiology, College for Public Health and Social Justice, Saint Louis University, St. Louis, MO.
authors.forename: Jen Jen
authors.initials: JJ
authors.lastname: Chang
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002585:Cesarean Section / Q000706:statistics & numerical data; D015331:Cohort Studies; D005260:Female; D005320:Fetal Macrosomia / Q000453:epidemiology; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D016015:Logistic Models; D008297:Male; D009765:Obesity / Q000453:epidemiology*; D016017:Odds Ratio; D011225:Pre-Eclampsia / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology*; D011256:Pregnancy Outcome; D047928:Premature Birth / Q000453:epidemiology; D012042:Registries; D012189:Retrospective Studies; D013851:Thinness / Q000453:epidemiology*; D055815:Young Adult
keywords: fetal outcomes; maternal outcomes; prepregnancy body mass index; subsequent pregnancy; uncomplicated pregnancy