title: Twin pregnancy, contrary to consensus, is a desirable outcome in infertility.
abstract: OBJECTIVE
  To determine whether the worldwide consensus that twin pregnancy after fertility treatment represents an adverse outcome to be avoided is correct.
  
  
  METHODS
  Literature search via PubMed and MEDLINE, going back to 1990.
  
  
  METHODS
  Academically affiliated private fertility center.
  
  
  METHODS
  Mothers and offspring in singleton and twin pregnancies.
  
  
  METHODS
  None.
  
  
  METHODS
  Maternal and perinatal/neonatal risks as well as cost considerations for singleton versus twin pregnancies.
  
  
  RESULTS
  Most risk assessments of twin pregnancies after fertility treatment have used spontaneous conceptions data, which reflect different treatment paradigms and outcome benefits from pregnancies after fertility treatments. In vitro fertilization (IVF) twins demonstrate approximately 40% lower outcome risks than spontaneous twin conceptions. Most risk assessments in the literature are calculated with pregnancy as the primary outcome, but in a fertility-treatment paradigm where patients want more than one child the statistically correct risk assessment should refer to born children as the primary reference. If published data are corrected accordingly to achieve statistical commonality of outcome (i.e., one child in singleton versus two children in twins), twin pregnancies no longer demonstrate a significantly increased risk profile and/or cost for mothers or individual offspring.
  
  
  CONCLUSIONS
  For infertile patients who want more than one child, twin deliveries represent a favorable and cost-effective treatment outcome that should be encouraged, in contrast to the current medical consensus.
authors.affiliation: The Center for Human Reproduction, New York, New York, USA. ngleicher@thechr.com
authors.forename: Norbert
authors.initials: N
authors.lastname: Gleicher
authors.forename: David
authors.initials: D
authors.lastname: Barad
mesh_terms: D002755:Choice Behavior; D003362:Cost-Benefit Analysis; D036861:Delivery, Obstetric / Q000009:adverse effects / Q000191:economics; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007247:Infertility, Female / Q000503:physiopathology* / Q000523:psychology; D011247:Pregnancy; D011256:Pregnancy Outcome; D018570:Risk Assessment; D012449:Safety; D014427:Twins / Q000523:psychology*