Biometry of the Fetal Heart between 10 and 17 Weeks of Gestation

Abstract

Objectives: Assessment of the dimensions of the cardiac chambers and the great arteries in the human fetus may be helpful in the prenatal diagnosis of congenital heart disease. The purpose of this prospective cross-sectional study was to compile normative data in fetal cardiac measurements in early pregnancy. The structure of the fetal heart was examined in 136 normal singleton fetuses between 10 and 17 weeks of gestation. Methods: The transversal heart diameter, both ventricular dimensions, interventricular septal thickness, heart area, heart circumference, thoracic diameter, thoracic circumference and thoracic area were measured in the four-chamber view during diastole. Diameters of the pulmonary trunk and ascending aorta were obtained in the short axis and long axis view during systole. Ultrasound examinations were performed with a 5.0-MHz transvaginal and/or transabdominal phased-array sector scanner. Results: The four-chamber view and the cross-over of the pulmonary artery and the aorta were adequately visualized in 44% of the fetuses at 10 weeks of gestation, in 75% at 11 weeks of gestation, in 93% at 12 weeks of gestation and in 100% of the fetuses at 13–17 weeks of gestation. Before 14 weeks of gestation transvaginal sonography was superior to the transabdominal sonography in visualization of the fetal heart and great arteries. After 14 weeks of gestation transabdominal sonography accurately demonstrated the structure of the fetal heart. The ratio of right and left ventricle (RV/LV) and the ratio of the pulmonary trunk and aorta (PT/AO) were constant during this period of gestation (approximately 1.00 and 1.10, respectively). The ratio of the cardiac and thoracic area showed only a slight increase with advancing gestational age, but with significant correlation. The fetal heart rate showed a slow decrease from 167 to 150 bpm in this period of gestation. The transversal heart diameter, both ventricular dimensions, interventricular septal thickness, heart area, cardiothoracic diameter ratio, aortic diameter and the pulmonary trunk diameter showed a highly significant linear correlation to the gestational age and the biparietal diameter. Conclusion: The advancing quality of ultrasound images allows fetal echocardiography in the first and early second trimester. Our normative data could be the basis of studying the development of cardiac structures in congenital heart disease and it might be helpful in the detection of some congenital heart defects in early pregnancy.

Cardiovascular Assessment of Fetal Mice by In Utero Echocardiography

“…In human fetuses, the embryonic pulse was first detected between days 26 and 32 at 80 bpm, then steadily increasing to 170 bpm at the end of the first trimester (Leiva et al 1999;Howe et al 1991). The increase in the ratio of heart and fetus areas with gestation age in mouse fetuses was similar to the increases in the ratio of heart/chest area and heart/chest diameter reported for human fetuses (Bronshtein et al 1992;Gembruch et al 2000). Mouse fetus area and heart area were also highly correlated to the crown-to-rump length as in human fetuses (Leiva et al 1999;Zimmer et al 1994).…”

Can a Complete Fetal Echocardiogram Be Performed at 12 to 16 Weeks' Gestation?

“…12,13 They found transvaginal imaging to be most helpful up to 13 weeks, whereas transabdominal imaging provides sufficient resolution after 13 weeks. Given this previous experience, our own reported experience, 21 and the work of others with successful prenatal detection of cardiac pathology, 17,19 we chose to routinely assess pregnancies at risk for CHD at our institution no earlier than 12 weeks, thus limiting need for reassessment in the late first trimester or early second trimester and the need for transvaginal imaging, not available in many FE programs.…”

“…This may have been related at least in part to the fact that our assessments were largely after 12 weeks, and in previous studies, transabdominal imaging at 13 to 14 weeks has been sufficient in the majority of pregnancies. 12,13 Although image resolution was better in many (particularly in at least one fetus with tetralogy of Fallot, allowing precise delineation of the defect), in general, imaging planes are somewhat dependent on fetal lie, given the limited range of movement of the transducer. In addition, imaging may be limited by distance from the transducer to the fetal thorax at older gestational ages, given the higher frequencies used by transvaginal probes, and we observed in a few patients that no additional information was obtained over the transabdominal images.…”

“…Since the early 1990s, many groups have reported their experience with imaging of the fetal heart at 10 to 16 weeks, but most have focused on imaging of basic fetal cardiac anatomy, including the four chambers and ventricular outflow tracts. [11][12][13] With technological advances in imaging and further experience, several investigators have documented successful prenatal detection of structural and functional abnormalities and arrhythmias at this early gestational age. 5,[14][15][16][17][18][19][20][21] None of these studies, however, have specifically evaluated the anatomic and functional details possible at <17 weeks with what is currently the standard approach in the midtrimester.…”

Transabdominal Sonographic Quantitative Analysis of the Fetal Cardiac Width in Third Trimester of Gestation

“…18 The introduction of high quality equipment, 19 as well as better understanding of fetal anatomy and physiology, has resulted in improved accuracy of fetal echocardiography in recent years. In fact, accuracy of complete anatomic assessment is now possible after 18 to 20 weeks gestation.…”