title: The power of observation.
abstract: OBJECTIVE
  In the golden age of evidence-based medicine, how should one view the cohort-controlled study of IVIG + anti-TNF-α (Humira) in recurrent in vitro fertilization (IVF) failure patients with an elevated Th1/Th2 cytokine production ratio.
  
  
  METHODS
  Critical analysis of the nature of evidence for causation.
  
  
  RESULTS
  A better delivery rate and a live birth rate per embryo approaching the estimated maximum possible in patients whose elevated Th1/Th2 ratio corrected to normal compared to those with an incomplete correction is a strong argument for causation. A maximal improvement when treatment was given 61-120 days before embryo transfer suggests a possible mechanism via improving the physiology during follicle development.
  
  
  CONCLUSIONS
  Independent replication to verify results would augment power.
authors: Departments of Medicine, Molecular Medicine & Pathology, & Ob-Gyn., McMaster University, 1200 Main Street West, Hamilton, ON, Canada. clarkd@mcmaster.ca
authors: David A
authors: DA
authors: Clark
mesh_terms: D005260:Female; D005307:Fertilization in Vitro / Q000187:drug effects*; D006801:Humans; D007247:Infertility, Female / Q000276:immunology*; D016753:Interleukin-10 / Q000378:metabolism*; D013601:T-Lymphocytes / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10