Cardiac circumference measurement: possible screening tool in early pregnancy for anomalous cardiac development

In this study, cardiac circumference (CC), measured by transvaginal sonography, was analyzed to determine the growth during the early stage of pregnancy and its relationship to abdominal circumference and femur length (FL).

Biometric measurements, including CC, were obtained in 1,182 euploid fetuses at 9-16 weeks' gestation. The CC measurements were related to gestational age (GA), abdominal circumference, and FL. The corresponding 95% confidence intervals were calculated.

A linear growth function was observed between CC (mm) and GA (days) (r2 = 0.601; p < 0.0001; y = 0.573 GA - 24.185). Similarly, a good correlation is described with a linear function between CC (mm) and abdominal circumference (mm) (r2 = 0.70; p < 0.0001; y = 0.343 AC + 3.696) and between CC (mm) and FL (mm) (r2 = 0.626; p < 0.0001; y = 1.335 FL + 14.444). The regression analysis that best correlates the dependent variable CC (mm) with the independent variables, GA (days), abdominal circumference (mm), and FL (mm), is: y = 0.137 GA + 0.235 AC + 0.199 FL - 3.303 (r2 = 0.708; p < 0.0001).

Our results provide normative data of the growth of the CC in early pregnancy. The good correlation described between CC and abdominal circumference and FL suggests that cardiac measurements in early pregnancy alone, or related to other fetal biometric parameters, could be used as a screening tool to identify fetuses at risk for abnormal heart development.