Abstract
Objective To examine the accuracy of early transvaginal fetal echocardiography (TV-echo) performed in a high-risk population.
Methods A series of 70 high-risk pregnancies were screened by TV-echo at 12–17 weeks' gestation between March 2000 and May 2001. A total of 74 fetal heart examinations were performed, including four twin pregnancies. For each fetus, visualization of the four-chamber view, the origin of the great arteries, and the aortic and arterial ductal arches was attempted in a segmental approach. B-mode and color/pulsed Doppler flow imaging were used in all cases, while M-mode was occasionally performed. The average duration of complete heart examination was approximately 30 min. All the examinations were performed by the same experienced operator. Reliability was assessed by conventional transabdominal echocardiography at 20–22 weeks, by postnatal follow-up in the first 3 months of life, and/or by autopsy in cases of termination of pregnancy.
Results The rate of successful visualization of the fetal heart was 90.5% (67/74). In 12 out of 74 fetuses, the final diagnosis was abnormal (16.2%), including ten structural heart abnormalities and two cases of heart dysfunction. In eight out often cases with structural heart defects, the diagnosis was suspected at early TV-echo. In three cases, although the main diagnosis was correct, details of cardiac defects were missed at early TV-echo. Among the heart defect group, five cases had an abnormal karyotype (41.7%) and nine cases showed extracardiac anomalies (75%). There were two false-negative cases at early TV-echo (two cases of hypoplastic left ventricle). There were no false-positive diagnoses. In our series, the sensitivity to detect congenital heart defects was 83% by transvaginal earl echocardiography and 80% by conventional transabdominal scan.
Conclusions High-frequency TV-echo can provide a comprehensive assessment of the fetal heart and can be achieved by 13–16 weeks' gestation. The high rate of successful visualization of the fetal heart provides a reliable diagnosis of major cardiac defects at this early stage of pregnancy. However, at present, this examination should be restricted to high-risk pregnancies.