title: Perinatal and neonatal outcomes in multiple gestations: assisted reproduction versus spontaneous conception.
abstract: OBJECTIVE
  Our purpose was to test the hypothesis that multiple pregnancies resulting from assisted reproductive therapy have a better outcome than those resulting from spontaneous conception.
  
  
  METHODS
  This was a retrospective cohort study. Cases came from pregnancies from assisted reproductive techniques. Controls were identified from spontaneous multiple pregnancies delivered in the same time period. Matching was done for maternal age, parity, fetal number, and presence of maternal medical problems. A total of 72 cases (56 twins and 16 triplets) and 124 controls (108 twins and 16 triplets) were studied. The primary outcome was perinatal mortality. Secondary outcomes were preterm delivery, birth weight, maternal complications, neonatal morbidity, and length of hospitalization.
  
  
  RESULTS
  Perinatal mortality is significantly increased in spontaneous twin gestations compared with twins resulting from assisted reproductive techniques (24 vs 2, P =.003). No difference is seen in the perinatal mortality in triplets. Mean gestational age at diagnosis was lower for twins and triplets resulting from assisted reproductive techniques (9.4 vs 13.3; P <.001 and 8.8 vs 15. 8; P <.001, respectively). Rate of cerclage and number of prenatal visits was higher for triplets in the assisted reproductive techniques group (P =.05 and.02, respectively). Mean gestational age at delivery, birth weight, rate of preterm labor, preterm premature rupture of membranes, pregnancy-induced hypertension, and incidence of gestational diabetes were not significantly different between the groups. No significant differences in neonatal morbidity were detected.
  
  
  CONCLUSIONS
  Assisted reproductive techniques-associated twins have lower perinatal mortality than spontaneously conceived twins. Perinatal and neonatal morbidity, gestational age at delivery, and birth weight are not affected by assisted reproductive techniques, even with closer surveillance and earlier gestational age at diagnosis in this group. Differences may be due to a higher frequency of monochorionic placentation in the spontaneously conceived group.
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: B P
authors.initials: BP
authors.lastname: Fitzsimmons
authors.forename: M W
authors.initials: MW
authors.lastname: Bebbington
authors.forename: M R
authors.initials: MR
authors.lastname: Fluker
mesh_terms: D000328:Adult; D001724:Birth Weight; D036861:Delivery, Obstetric; D005260:Female; D005306:Fertilization / Q000502:physiology; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D007226:Infant Mortality; D007231:Infant, Newborn / Q000502:physiology*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology; D011256:Pregnancy Outcome; D011272:Pregnancy, Multiple; D012099:Reproductive Techniques; D012189:Retrospective Studies; D014310:Triplets; D014427:Twins