Predictive values of first trimester ultrasound screening for twin-to-twin transfusion syndrome and selective intrauterine growth restriction in monochorionic twin pregnancies

Background : Monochorionic diamniotic (MCDA) twins have a substantially higher risk for perinatal morbidity and mortality due to the presence of placental vascular anastomoses between the twins. Objectives: The primary purpose of this research was to confirm the accuracy of first trimester ultrasonography in predicting selective intrauterine growth restriction (SIGR) and twin-to-twin transfusion syndrome (TTTS) in monochorionic twin pregnancies using the triad of nuchal translucency (NT), cord insertion and inter-twin discordance in foetal size. Patients and methods: This was a prospective cohort study that included 31 pregnant women who were carrying monochorionic twins during the first trimester. The research was carried out at a foetal medicine unite, Obstetrics and Gynecology Department, South Valley University Hospital. The duration of the study ranged from 18 to 24 months. Results : the mean difference in NT can determine TTTS with fair sensitivity (73.2%) and high specificity (100%) in twins (p<0.001). Likewise, mean difference in CRL can determine TTTS with fair sensitivity (73.1%) and high specificity (100%) in twins (p<0.001).The mean difference in NT can determine sIUGR with high sensitivity (100%) and fair specificity (73.2%) in twins (p<0.001). Likewise, mean difference in CRL can determine sIUGR with high sensitivity (100%) and fair specificity (73.1%) in twins (p<0.001). Conclusion : we have demonstrated that NT and CRL were significantly higher in TTTS group, and NT and CRL were respectively identified as the predictive markers for sIUGR and TTTS.