Abstract
BackgroundPlacental anastomoses in monochorionic diamniotic (MCDA) twin pregnancy have a major impact on fetal circulation. This study was designed to define reference ranges of cardiac and vascular Doppler indices in MCDA twin pregnancies.MethodsThis cross-sectional study included 442 uncomplicated MCDA twin fetuses undergoing Doppler ultrasonography at 18–35 weeks of gestation. Left and right myocardial performance index (LV-MPI, RV-MPI), E/A ratio of atrioventricular valves, pulsatility indices of umbilical artery, middle cerebral artery (MCA), and ductus venosus (DV), cerebroplacental ratio, peak systolic velocity of MCA, S/a ratio of DV, and early diastolic filling time of ductus venosus (DV-E) were evaluated under standardized settings. The equation models between Doppler indices and gestational age (GA) were fitted. After adjustment for GA, the correlations between MPI and fetal heart rate (FHR), and between MPI and DV indices were analyzed.ResultsEstimated centiles of Doppler indices were derived as a function of GA, being distinct in values from those of singletons. There was no correlation between GA-adjusted MPI and FHR. DV-E was inversely related to LV-MPI.ConclusionsMCDA twins showed significant changes in some Doppler indices throughout gestation with quantitative differences from singletons, emphasizing the importance of MC twin-specific reference values for clinical application. Further adjustment of MPI for FHR was unnecessary. DV-E is a vascular index indirectly representing fetal diastolic function.
Highlights
Placental anastomoses in monochorionic diamniotic (MCDA) twin pregnancy have a major impact on fetal circulation
We explored whether any ductus venosus (DV) indices correlated with myocardial performance index (MPI) to find the vascular index indirectly representing cardiac diastolic function
A total of 450 fetuses were enrolled in the study, and the population analyzed was restricted to 442 fetuses (Table S1)
Summary
Placental anastomoses in monochorionic diamniotic (MCDA) twin pregnancy have a major impact on fetal circulation. This study was designed to define reference ranges of cardiac and vascular Doppler indices in MCDA twin pregnancies. The fetal myocardial performance index (MPI) and E/A ratio of flow across the atrioventricular valve are common parameters for cardiac function assessment, whereas umbilical artery (UA), middle cerebral artery (MCA), and ductus venosus (DV) waveforms are customarily evaluated in MCDA twin pregnancies. A few studies in literature have examined normal Doppler indices in MCDA twin pregnancies with distinct study designs, ultrasound settings, and statistical analyses [11, 13,14,15]. We performed a study on a prospective cohort of MCDA twin fetuses under a well-suited ultrasound setting to construct normative values of cardiac and vascular Doppler indices pragmatically used for surveillance. We explored whether any DV indices correlated with MPI to find the vascular index indirectly representing cardiac diastolic function
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
