Embryonic and Fetal Heart Development Before 12 Weeks of Gestation

To assess embryonic and fetal cardiac growth and development using transvaginal 2-dimensional sonography before 12 weeks of gestation.

Transvaginal scans for first-trimester dating were performed for 131 normal fetuses at 8-11 + 6 weeks of gestation. The basal-apical length (BAL), transverse length (TL), cardiac circumference (ECC), embryonic cardiac area (ECA), global sphericity index (GSI), and cardio-thoracic area ratio (CTAR) were able to be obtained in 105 normal embryos and fetuses.

Nomograms for several cardiac parameters including BAL, TL, ECC, ECA, GSI, and CTAR were constructed. BAL, TL, ECC, and ECA increased curvilinearly with advancing gestation (R² = 0.97406, 0.980396, 0.978359, and 0.920705, respectively, P < .001). GSI (mean, 1.14; SD, 0.10) and CTAR (mean, 15.7%; SD, 3.3%) values were constant at 8-11 + 6 weeks of gestation. There were significant curvilinear correlations between BAL, TL, ECC, and ECA, and crown-rump length (CRL) (R² = 0.975976, 0.983482, 0.980673, and 0.929936, respectively, P < .001). GSI and CTAR values were not changed with the increase of CRL during this period.

Our results provide nomograms for several cardiac parameters which may improve the understanding of embryonic and fetal cardiac growth and development prior to 12 weeks of gestation.