José Carlos Areias

Anticipating twin-twin transfusion syndrome in monochorionic twin pregnancy. Is there a role for nuchal translucency and ductus venosus blood flow evaluation at 11-14 weeks?

Twin-twin transfusion syndrome is a major complication of monochorionic twin pregnancies. In foetuses from monochorionic twinning the presence of increased nuchal translucency thickness (NT) has been associated with an increased risk of developing this syndrome. One of the presumed mechanisms of increased NT is early cardiac failure, indirectly indicated by abnormal blood flow in the ductus venosus. We present eleven cases of monochorionic twin pregnancies in which nuchal translucency thickness and ductus venosus blood flow evaluation was per formed at 11-14 weeks. In the two cases presenting with nuchal translucency discrepancy between the two foetuses along with anomalous ductus venosus blood flow in the foetus with increased nuchal translucency, twin-twin transfusion syndrome (TTTS) eventually developed. In none of the twins displaying no inter-twin difference in NT measurements and in those with discrepant NT but normal flow in both ductus venosus, was the progression to TTTS observed. In the two cases which developed TTTS, foetoscopic laser coagulation of the vascular anastomosis was successfully carried out at 18weeks and normalisation of the venous return was registered. These findings suggest that the association of increased NT and abnormal flow in the ductus venosus in monochorionic twins may be an early manifestation of haemodynamic imbalance between the donor and the recipient eventually manifested as twin-twin transfusion syndrome. Further studies, however, are necessary to establish the potential role of the combination of NT and ductus venosus blood flow assessment as a screening method for TTTS.

Early Antenatal Diagnosis of Cardiac Defects Using Transvaginal Doppler Ultrasound: New Perspectives?

Objective: Cardiac defects are the most prevalent congenital anomalies. Screening policies have adopted an 18- to 22-week ultrasound scan to detect such anomalies. However, diagnosis may be feasible early in pregnancy using transvaginal Doppler ultrasound. Methods: Transvaginal ultrasound, including nuchal translucency (NT) measurement, is routinely performed at 10–13 weeks of gestation at our department. Complementary arterial and venous blood flow Doppler evaluation is also performed in cases of increased NT as a part of an ongoing research project. Results: Ultrasound revealed complete atrioventricular septal defects in 2 trisomic fetuses (trisomy 18 and 21) at 12 and 13 weeks of gestation, respectively, with increased NT and abnormal venous blood flow velocity. Conclusions: Incrased NT has been associated with major chromosomal anomalies and is being increasingly related to cardiac defects. Considering that venous blood flow patterns may provide additional clues to the cardiac function, it may be useful as a complementary tool for the earlier diagnosis of structural cardiac anomalies.