The normal growth of the thoracic aorta in human foetuses.

The present study was performed on 128 spontaneously aborted human foetuses aged 15-34 weeks in order to establish normal values for thoracic aorta dimensions at various gestational ages. Using anatomical dissection, digital-image analysis (the Leica QWin Pro 16 system) and statistical analysis (ANOVA, regression analysis) the growth of the length, the original and terminal external diameters and the volume of the thoracic aorta during gestation was examined. No significant gender differences were found (p>0.05). The growth curves were generated of the best fit for the plot for each morphometric feature against gestational age. Both the length and external diameters of the thoracic aorta increased in proportion to the advance in foetal age. The length ranged from 12.49+/-1.85 mm to 48.82+/-6.31 mm according to the linear function y=-19.654+2.0512x+/-3.5168. The original external diameter ranged from 1.25+/-0.28 mm to 5.65+/-0.48 mm according to the linear fashion y=-2.3834+0.2367x+/-0.3850. The terminal external diameter ranged from 1.15+/-0.26 mm to 5.18+/-0.45 mm, in agreement with the linear model y=-2.1438+0.2156x+/-0.3555 (r=0.96, p<0.001 for each feature). The volume of the thoracic aorta ranged from 15.75+/-8.06 mm3 to 1158.01+/-301.85 mm3 according to the quadratic function y=1376.2-154.42x+4.419x2+/-125.6 (R2=0.90). The growth curves generated from my data may be useful as a reference for foetal echocardiographers, who must distinguish abnormal from normal foetal development.