RESUMEN
OBJECTIVE: To describe the dimensions and amount of collagen in the aortic root of autopsied fetuses at different gestational ages. MATERIAL AND METHODS: 40 samples of aortic roots were selected from autopsied fetuses with gestational ages ranging between 20 and 40 weeks. The thickness and the area of the aortic wall were analyzed on slides stained with Hematoxylin and Eosin, and the collagen was quantified on slides stained with Picrosirius, by using an image analyzing system. RESULTS: A positive correlation was observed between the thickness of the media layer of the aortic wall and the gestational age. There was a positive and significant correlation between the percentage of collagen in the aortic wall with gestational age and fetal weight. The correlation between gestational age and the area of the aortic root circumference was positive and significant. And the correlation between the aortic diameter and the gestational age as well as fetal length was positive and significant. CONCLUSION: The thickness of the media layer, the amount of collagen in the aortic wall, the area of the aortic root circumference and the aortic diameter rose with the increase of the gestational age. Thus, the morphological analysis of the aortic root may help as a parameter during the follow-up of inter-uterine growth and fetal development.