Abnormal placental cord insertion may induce intrauterine growth restriction in IVF-twin pregnancies

BACKGROUND: This study determined whether twins conceived through assisted reproduction technology (ART) have an increased risk of perinatal complications compared with natural twin pregnancies and investigated potential associated major risk factors. METHODS: This retrospective study consisted of 199 twins born between 1994 and 2003. There were four groups according to conception modalities: 97 twins after spontaneous pregnancy, 24 after induced ovulation, 28 after intrauterine insemination (IUI) and 50 after IVF with embryo transfer. Analysis included preterm birth, Caesarean delivery, weight discordance, intrauterine growth restriction (IUGR), low-birth-weight, Apgar score, chorionicity, gross placental pathology and placental umbilical cord insertion (UCI) site. RESULTS: A significant difference was found in IUGR between the IVF group (7.0%) and spontaneous pregnancy group (14.9%). When maternal age was > 30 years there was a 2.86-fold increase in the risk of IUGR. There was a 3.69-fold increased risk of IUGR in the presence of abnormal UCI (odds ratio 3.69, 95% CI 1.62-8.42) and a 2.18-fold increased risk of abnormal UCI in monochorionic twins when compared with dichorionic twins (odds ratio 2.18, 95% CI 1.30-3.66). CONCLUSION: Twins conceived through ART are not at an increased risk of perinatal complications. A relationship has been found between abnormal UCI and IUGR.