title: [Premature twins: clinic comparison, reproductive assisted techniques versus spontaneous conception].
abstract: BACKGROUND
  Twin pregnancies occur one out of every 800. Due to the increase in maternal age and infertility, the use of assisted reproductive technology (ART) has risen. Thirty five percent of pregnancies solved using ART are twin pregnancies. A RT consists of infertility treatments in which oocytes and sperm are manipulated. The objective of this study was to compare the clinical behavior of premature twins born through ART versus those born after spontaneous conception (SC).
  
  
  METHODS
  Retrolective cohort study. The data was obtained from the records of preterm twins born between August 2010 and August 2013. Preterm twins were categorized in two groups: the ones conceived using ART versus those conceived through SC. Demographic characteristics and neonatal outcomes were compared.
  
  
  RESULTS
  The total was of 398 patients: 208 conceived in consequence of ART and 190 through SC. The primary outcome and neonatal morbidities showed no significant difference, only the incidence of necrotizing enterocolitis and the use of parenteral nutrition showed significant difference. The length of hospital stay between groups was similar.
  
  
  CONCLUSIONS
  In our population of preterm twins, the mode of conception had no detectable effect on mortality or short term morbidities.
authors.affiliation: Servicio de Neonatología, División de Pediatría, Hospital Español de México, Distrito Federal, México. noriegarox@gmail.com.
authors.forename: Roxana
authors.initials: R
authors.lastname: Noriega-Alvarez
authors.forename: José
authors.initials: J
authors.lastname: Iglesias-Leboreiro
authors.forename: Isabel
authors.initials: I
authors.lastname: Bernardez-Zapata
mesh_terms: D015331:Cohort Studies; D005260:Female; D005306:Fertilization; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000453:epidemiology; D008297:Male; D011247:Pregnancy; D059285:Pregnancy, Twin / Q000706:statistics & numerical data*; D047928:Premature Birth / Q000453:epidemiology*; D027724:Reproductive Techniques, Assisted; D012189:Retrospective Studies
keywords: Infant, Premature; Reproductive techniques, Assisted; Spontaneous conception; Twins