title: The impact of increasing obesity class on obstetrical outcomes.
abstract: OBJECTIVE
  Nationally, rates of obesity continue to rise, resulting in increased health concerns for women of reproductive age. Identifying the impact of maternal obesity on obstetrical outcomes is important to enhance patient care.
  
  
  METHODS
  We conducted a retrospective cohort study of 6674 women who delivered a singleton infant at ≥ 20 weeks' gestation between December 1, 2007, and March 31, 2010, at The Ottawa Hospital. Maternal pre-pregnancy BMI was used to classify women into normal, overweight, and obese (class I/II/III) categories according to WHO classifications. Obstetrical outcomes among obese women were compared with those of women with normal BMI. Multivariable regression models were used to determine adjusted odds ratios and 95% confidence intervals.
  
  
  RESULTS
  Compared with women with normal BMI, obese women had significantly higher rates of preeclampsia, gestational hypertension, and gestational diabetes, and these rates increased with increasing BMI (trend-test P < 0.001). There was a significant increase in rates of induction of labour in the obesity categories, from 25.3% in women with normal BMI to 42.9% in women with class III morbid obesity (aOR 1.67; 95% CI 1.43 to 1.93). Rates of primary Caesarean section rose with increasing BMI and were highest in women with class III morbid obesity (36.2% vs. 22.1% in women with normal BMI) (aOR 1.46; 95% CI 1.23 to 1.73).
  
  
  CONCLUSIONS
  Increasing BMI is associated with increasing rates of preeclampsia, gestational hypertension, and gestational diabetes. There is a significant increase in rates of induction of labour with increasing obesity class, and a significantly increased Caesarean section rate with higher BMI. Obstetrical care providers should counsel obese patients about the risks they face and the importance of weight loss before pregnancy.
authors.affiliation: Department of Obstetrics, Gynecology and Newborn Care, The Ottawa Hospital, Ottawa ON; Department of Obstetrics and Gynecology, Faculty of Medicine, University of Ottawa, Ottawa ON.
authors.forename: Darine
authors.initials: D
authors.lastname: El-Chaar
authors.affiliation: Obstetrics & Maternal Newborn Investigations (OMNI), The Ottawa Hospital, Ottawa ON.
authors.forename: Sara A
authors.initials: SA
authors.lastname: Finkelstein
authors.affiliation: Shanghai Institute of Planned Parenthood Research, Shanghai, China.
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Tu
authors.affiliation: Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa ON; Better Outcomes Registry & Network (BORN) Ontario, Children's Hospital of Eastern Ontario, Ottawa ON.
authors.forename: Deshayne B
authors.initials: DB
authors.lastname: Fell
authors.affiliation: Department of Obstetrics, Gynecology and Newborn Care, The Ottawa Hospital, Ottawa ON; Division of Maternal Fetal Medicine, The Moncton Hospital, Horizon Health Network, Moncton NB.
authors.forename: Laura
authors.initials: L
authors.lastname: Gaudet
authors.affiliation: Department of Obstetrics, Gynecology and Newborn Care, The Ottawa Hospital, Ottawa ON; Department of Obstetrics and Gynecology, Faculty of Medicine, University of Ottawa, Ottawa ON.
authors.forename: Jacques
authors.initials: J
authors.lastname: Sylvain
authors.affiliation: Department of Obstetrics, Gynecology and Newborn Care, The Ottawa Hospital, Ottawa ON; Department of Obstetrics and Gynecology, Faculty of Medicine, University of Ottawa, Ottawa ON.
authors.forename: George
authors.initials: G
authors.lastname: Tawagi
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, University of Ottawa, Ottawa ON; Obstetrics & Maternal Newborn Investigations (OMNI), The Ottawa Hospital, Ottawa ON; Department of Epidemiology and Community Medicine, Faculty of Medicine, University of Ottawa, Ottawa ON; Clinical Epidemiology Program, Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa ON.
authors.forename: Shi
authors.initials: S
authors.lastname: Wu Wen
authors.affiliation: Department of Obstetrics, Gynecology and Newborn Care, The Ottawa Hospital, Ottawa ON; Department of Obstetrics and Gynecology, Faculty of Medicine, University of Ottawa, Ottawa ON; Obstetrics & Maternal Newborn Investigations (OMNI), The Ottawa Hospital, Ottawa ON; Better Outcomes Registry & Network (BORN) Ontario, Children's Hospital of Eastern Ontario, Ottawa ON.
authors.forename: Mark
authors.initials: M
authors.lastname: Walker
mesh_terms: D000328:Adult; D015992:Body Mass Index; D001835:Body Weight; D002585:Cesarean Section / Q000706:statistics & numerical data; D016640:Diabetes, Gestational / Q000453:epidemiology; D005260:Female; D006801:Humans; D007751:Labor, Induced / Q000706:statistics & numerical data; D015999:Multivariate Analysis; D009765:Obesity / Q000145:classification* / Q000453:epidemiology*; D009864:Ontario / Q000453:epidemiology; D050177:Overweight / Q000453:epidemiology; D011225:Pre-Eclampsia / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000145:classification* / Q000453:epidemiology*; D012189:Retrospective Studies; D055815:Young Adult