title: Twin pregnancy among women with pregestational type 1 or type 2 diabetes mellitus.
abstract: OBJECTIVE
  To assess the impact of twin versus singleton pregnancy on obstetric and perinatal outcomes among women with pregestational diabetes mellitus (DM).
  
  
  METHODS
  Multicenter retrospective cohort study of women with pregestational DM and twin or singleton pregnancy, conducted in Spain during 2005-2010. Each group included 63 women (type 1 DM, n=39; type 2 DM, n=24).
  
  
  RESULTS
  Of 269 565 deliveries, 68 (0.025%) were twins of mothers with pregestational DM, with 28/63 (44.4%) conceptions achieved with assisted reproduction technology. Among women with type 1 DM, hypertensive complications were more common among those with twins than among controls (13% versus 3%, P=0.02); the rate of preterm birth was higher (69% versus 15%, P<0.001); and the rate of admission to the neonatal intensive care unit was higher (51% versus 21%, P=0.005). Twin pregnancy was an independent risk factor for adverse perinatal outcomes regardless of the type of diabetes.
  
  
  CONCLUSIONS
  Twin pregnancy in women with either type of DM dramatically increased the risk of perinatal morbidity. In mothers with type 1 DM, twin pregnancy was more often associated with hypertensive complications than singleton pregnancy. Transfer of more than one embryo should be avoided if ART is needed in a woman with DM.
authors.affiliation: Departamento de Obstetricia y Ginecología, Hospital Universitario de Canarias, Tenerife, Spain. Electronic address: ngonzalezg@sego.es.
authors.forename: Nieves L
authors.initials: NL
authors.lastname: González González
authors.affiliation: Departamento de Estadística, I.O. y Computación, Universidad de La Laguna, Tenerife, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: González Dávila
authors.affiliation: Departamento de Obstetricia y Ginecología, Hospital Vall'de Hebrón, Barcelona, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Goya
authors.affiliation: Departamento de Obstetricia y Ginecología, Hospital Universitario Materno Infantil de Canarias, Las Palmas de Gran Canaria, Spain.
authors.forename: Begoña
authors.initials: B
authors.lastname: Vega
authors.affiliation: Departamento de Obstetricia y Ginecología, Hospital Universitario de Canarias, Tenerife, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Hernández Suarez
authors.affiliation: Departamento de Obstetricia y Ginecología, Hospital Universitario La Paz, Madrid, Spain.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Bartha
mesh_terms: D000328:Adult; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D005260:Female; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000209:etiology*; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D011254:Pregnancy in Diabetics; D059285:Pregnancy, Twin; D027724:Reproductive Techniques, Assisted; D012189:Retrospective Studies
keywords: Assisted reproduction technology; Diabetes mellitus; Perinatal outcomes; Pregestational diabetes mellitus; Twin pregnancy; Twins; Type 1 diabetes; Type 2 diabetes