title: [Perinatal outcomes of twin pregnancies conceived through in vitro fertilization versus spontaneous].
abstract: OBJECTIVE
  Determine maternal and fetal characteristics of in vitro fertilization twin pregnancies in comparison with spontaneous twin pregnancies.
  
  
  METHODS
  Retrospective historical cohort study between 2011 and 2013. Statistical analysis was performed with SPSS 15.0 program and Epidat 3.0. A value of p<0.05 was considered statistically significant.
  
  
  RESULTS
  96 twin pregnancies met inclusive criteria with an incidence of 2.01%, of which 54.16% were spontaneous twin pregnancies and 45.83% in vitro fertilization twin pregnancies. Mean maternal age at delivery was higher in vitro fertilization twin pregnancies (p=0.004). The primigravidae were more frequent in vitro fertilization twin pregnancies group (p<0.001). Monochorionic pregnancies percentage was superior in spontaneous pregnancies (p=0.009). Amenorrhea at delivery was not a significant difference between cohorts (p=.9). Preterm rate was superior in spontaneous twin pregnancies group (p=0.003). However, "great preterm deliveries" were higher in in vitro fertilization twin pregnancies (p<0.001). Significant differences were not observed in fetal presentation at delivery, first-born child birth-weight or intrauterine growth retardation between the two groups. Nevertheless, the mean birth-weight of second-born spontaneously conceived twins was higher than second-born twins of the in vitro fertilization conceived group (p=0.027). Gestational pathology presented the same distribution in both cohorts. There was no significant difference in the mode of delivery between the two groups. Total perinatal mortality rate was 20,83%o and comprised 2 first born twins and 2 second born twins. Three of the stillbirths came from the spontaneous pregnancies group and one from the in vitro fertilization group.
  
  
  CONCLUSIONS
  Perinatal death was secondary to stillbirths, which we found higher in spontaneously conceived twin pregnancies due to higher number of monochorionic pregnancies.
authors: Paula
authors: P
authors: Rubio-Cid
authors: E
authors: E
authors: Alvarez-Silvares
authors: María Teresa
authors: MT
authors: Aves-Pérez
authors: Sandra
authors: S
authors: García-Lavandeira
authors: Marta
authors: M
authors: Pérez-Adán
mesh_terms: D000328:Adult; D001724:Birth Weight; D015331:Cohort Studies; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007231:Infant, Newborn; D008423:Maternal Age; D008875:Middle Aged; D054238:Perinatal Mortality; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology*; D011256:Pregnancy Outcome; D059285:Pregnancy, Twin; D012189:Retrospective Studies; D050497:Stillbirth / Q000453:epidemiology; D014427:Twins; D055815:Young Adult