title: The impact of maternal body mass index on in vitro fertilization outcomes.
abstract: OBJECTIVE
  To examine the effect of body mass index on gonadotropin dose requirements for ovarian stimulation, as well as other clinical outcomes in women undergoing in vitro fertilization.
  
  
  METHODS
  We performed a retrospective cohort study involving 752 women undergoing a total of 951 IVF or IVF-ICSI cycles at a private fertility clinic between January 2007 and May 2011. The 951 treatment cycles were divided into three groups according to the weight of the women involved: normal weight (BMI < 25 kg/m², 461 cycles), overweight (25 ≤ BMI < 30 kg/m², 277 cycles), and obese (BMI ≥ 30 kg/m², 179 cycles). Total gonadotropin dose requirements and clinical IVF cycle outcomes (cycle cancellation, clinical pregnancy, and live birth) were compared between the three BMI groups. We performed multivariable analyses, adjusting for potential confounders such as age at cycle start, day 3 serum FSH level, smoking, presence of polycystic ovary syndrome, and duration of infertility.
  
  
  RESULTS
  There were no significant differences between the three BMI groups for any of the IVF cycle outcomes measured, including the total FSH dose required for ovarian stimulation. The likelihood of cycle cancellation, clinical pregnancy, and live birth were not significantly different between normal weight, overweight, and obese women.
  
  
  CONCLUSIONS
  Obese women did not require significantly higher doses of gonadotropins for ovarian stimulation than normal weight individuals. At our centre, female obesity did not significantly affect the clinical outcomes of IVF treatment. However, given the conflicting results of existing studies, the effect of maternal obesity on IVF outcomes remains unclear.
authors.affiliation: Department of Obstetrics and Gynaecology, Dalhousie University, Halifax NS.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Legge
authors.affiliation: Department of Obstetrics and Gynaecology, Dalhousie University, Halifax NS.
authors.forename: Renda
authors.initials: R
authors.lastname: Bouzayen
authors.affiliation: Department of Obstetrics and Gynaecology, Dalhousie University, Halifax NS.
authors.forename: Linda
authors.initials: L
authors.lastname: Hamilton
authors.affiliation: Department of Obstetrics and Gynaecology, Dalhousie University, Halifax NS.
authors.forename: David
authors.initials: D
authors.lastname: Young
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D005307:Fertilization in Vitro; D006062:Gonadotropins / Q000008:administration & dosage*; D006801:Humans; D009765:Obesity; D050177:Overweight; D010062:Ovulation Induction; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D006062:Gonadotropins
keywords: body mass index; in vitro fertilization; live birth; obesity