title: Risk of obstetric anal sphincter lacerations among obese women.
abstract: OBJECTIVE
  To assess the risk for obstetric anal sphincter lacerations in relation to maternal obesity among primiparous women in Sweden.
  
  
  METHODS
  A population-based study.
  
  
  METHODS
  Sweden.
  
  
  METHODS
  All women with vaginal delivery and singleton pregnancy in Sweden in the years 2003-2008 (n = 210,678).
  
  
  METHODS
  The Medical Birth Registry, the National Board of Health and Welfare, was used to identify cases of rupture and body mass index (BMI) classes. The population was categorised into four classes with BMI of <25, 25 to <30, 30 to <35 and >35 kg/m².
  
  
  METHODS
  Odds ratios were estimated with 95% confidence intervals. In order to estimate the effect of BMI on obstetric anal sphincter lacerations, with possible confounders accounted for, uni- and multivariate logistic regressions were performed.
  
  
  RESULTS
  In total, 8958 (4.25%) cases of anal sphincter lacerations (grade III-IV) occurred; increasing BMI showed a significant near-dose-response type of protective effect against grade III-IV lacerations when compared with women with BMI <25 kg/m²: BMI 25 to <30 kg/m², 0.89; BMI 30 to <35 kg/m², 0.84; BMI > 35 kg/m², 0.70.
  
  
  CONCLUSIONS
  Overweight and obesity were associated with a decreased risk for obstetric anal sphincter lacerations.
authors: Division of Obstetrics and Gynecology, Department of Clinical Science, Karolinska Institutet at Danderyd Hospital, Stockholm, Sweden. elisabeth.storck-lindholm@ds.se
authors: E S
authors: ES
authors: Lindholm
authors: D
authors: D
authors: Altman
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000293:injuries*; D015992:Body Mass Index; D002585:Cesarean Section / Q000706:statistics & numerical data*; D036861:Delivery, Obstetric / Q000009:adverse effects / Q000706:statistics & numerical data*; D017558:Elective Surgical Procedures; D005242:Fecal Incontinence / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D006801:Humans; D022125:Lacerations / Q000453:epidemiology*; D009765:Obesity / Q000453:epidemiology*; D007744:Obstetric Labor Complications / Q000453:epidemiology* / Q000517:prevention & control; D016017:Odds Ratio; D010298:Parity; D011247:Pregnancy; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology
keywords: Anal sphincter tears; obesity; pregnancy