title: Lower embryonic loss rates among twin gestations following assisted reproduction.
abstract: OBJECTIVE
  To determine whether maternal age and number of transferred embryos influence early pregnancy losses in twin pregnancies compared to singletons following IVF/ICSI.
  
  
  METHODS
  We compared the pregnancy loss rates in singleton (n = 549) and twin (n = 252) gestations, stratified by maternal age (< or = 35 and > 35 years) and the number of transferred embryos (1-3 and 4-9).
  
  
  RESULTS
  Loss rates of singleton pregnancies were significantly higher than that in twins (OR 3.0, 95% CI 1.9, 4.9), especially among singletons conceived after transfer of 4-9 embryos (OR 5.0, 95% CI 2.2, 11.9). Younger mothers of twins had lower loss rates (OR 0.3, 95% CI 0.1, 0.9).
  
  
  CONCLUSIONS
  Twins have a significantly reduced spontaneous miscarriage rate compared with singletons following IVF/ICSI. Higher implantation rates per cycle (i.e., development of twins rather than one live embryo) may represent a better capacity of the uterus for early embryonic development.
authors.affiliation: Department of Obstetrics and Gynecolgy, Arcispedale Santa Maria Nuova, Reggio Emilia, Italy.
authors.forename: G B
authors.initials: GB
authors.lastname: La Sala
authors.forename: G
authors.initials: G
authors.lastname: Nucera
authors.forename: A
authors.initials: A
authors.lastname: Gallinelli
authors.forename: A
authors.initials: A
authors.lastname: Nicoli
authors.forename: M T
authors.initials: MT
authors.lastname: Villani
authors.forename: I
authors.initials: I
authors.lastname: Blickstein
mesh_terms: D000022:Abortion, Spontaneous / Q000209:etiology*; D000328:Adult; D047108:Embryonic Development / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008423:Maternal Age; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011272:Pregnancy, Multiple; D011446:Prospective Studies; D020554:Sperm Injections, Intracytoplasmic / Q000009:adverse effects*; D014427:Twins