title: Impact of bodyweight/body mass index on the effectiveness of emergency contraception with levonorgestrel: a pooled-analysis of three randomized controlled trials.
abstract: OBJECTIVE
  A pooled analysis of two randomized controlled trials (RCTs) suggested that increased bodyweight and body mass index (BMI) may be associated with a greater probability of pregnancy. To address this issue we investigated whether higher bodyweight and/or BMI negatively impacted the risk of pregnancy in women receiving LNG-EC (levonorgestrel - emergency contraception) after unprotected sexual intercourse in a pooled analysis of three large multinational RCTs conducted by the World Health Organization (WHO).
  
  
  METHODS
  A pooled analysis of three double-blind, multinational RCTs conducted by the WHO to investigate the efficacy of LNG-EC in the general population. All analyses were done on the per-protocol set (PPS) which included 5812 women who received LNG-EC within 72 hours following unprotected sexual intercourse. The analysis was based on logistic regression, with pregnancy as the outcome. BMI and weight were represented in the same model.
  
  
  RESULTS
  A total of 56 pregnancies were available for analysis in the PPS. Increasing bodyweight and BMI were not correlated with an increased risk of pregnancy in the studied population. A limitation of this study is that despite the large study population in the pooled analysis there were relatively small numbers of women in the high-BMI and high-bodyweight subgroups.
  
  
  CONCLUSIONS
  LNG-EC is effective for preventing pregnancy after unprotected intercourse or contraceptive failure and no evidence was found to support the hypothesis of a loss of EC efficacy in subjects with high BMI or bodyweight. Therefore, access to LNG-EC should not be limited only to women of lower bodyweight or BMI.
authors.affiliation: a a Dept. of Women's and Children's Health, Division of Obstetrics and Gynecology, Karolinska Institutet, Karolinska University Hospital , Stockholm , Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Gemzell-Danielsson
authors.affiliation: b b Department of Clinical Pharmacology , Infectology, Immunology and Allergology, Kenezy Gyula Hospital , Debrecen , Hungary.
authors.forename: L
authors.initials: L
authors.lastname: Kardos
authors.affiliation: c c Concept Foundation Campus Biotech , Geneva , Switzerland.
authors.forename: H
authors.initials: H
authors.lastname: von Hertzen
mesh_terms: D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D001835:Body Weight; D044363:Contraception, Postcoital / Q000379:methods*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D016912:Levonorgestrel / Q000008:administration & dosage* / Q000009:adverse effects; D008875:Middle Aged; D050177:Overweight / Q000150:complications*; D011247:Pregnancy; D016032:Randomized Controlled Trials as Topic; D014944:World Health Organization; D055815:Young Adult
chemical_list: D016912:Levonorgestrel
keywords: Body mass; Bodyweight; Contraception failure; Emergency contraception; Levonorgestrel