RESUMO
OBJECTIVE: Determine maternal and fetal characteristics of in vitro fertilization twin pregnancies in comparison with spontaneous twin pregnancies. MATERIAL AND 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.
