Echocardiography in early pregnancy: review of literature.

OBJECTIVE: First-trimester transvaginal sonography is a widely used technique to examine the fetus early in pregnancy. The aim of this review was to explore the possibilities of examining the fetal heart at this early stage of pregnancy. METHODS: With the use of a computerized database (PubMed, US National Library of Medicine, Bethesda, MD), articles on first-trimester echocardiography were retrieved. Furthermore, the cited references of the studied articles were used to find additional articles. RESULTS: In the analyzed articles, an increase in visualization rates of the 4-chamber view and the outflow tracts was shown in the last decade, with visualization rates of greater than 90% at 13 weeks' gestation. The different cardiac defects that are shown in first-trimester fetuses are mainly defects involving the 4-chamber view, indicating that defects solely affecting the outflow tracts are difficult to diagnose in the first trimester of pregnancy. The sonographic assessment of the fetal heart between 14 and 18 weeks' gestation has been described. The literature, however, has not shown clear advantages of performing fetal echocardiography during this period compared with transvaginal sonography at 13 weeks' gestation. CONCLUSIONS: First-trimester echocardiography is a promising technique, which can be of considerable value for patients at risk of having offspring with cardiac defects. This technique is, however, currently limited to a few specialized centers.