Development of the abdominal aorta and iliac arteries during the fetal period: a morphometric study

This study aimed to determine the location and morphometric development of the fetal abdominal aorta and the iliac arteries.

The study was carried out between 1996 and 2008 on 172 spontaneously aborted human fetuses (76 males and 96 females) aged between 9 and 40 weeks. None of the fetuses had any external pathology or anomaly. The location of the abdominal aorta was determined in reference to the vertebral column. This was followed by measurements of the lengths, external diameters of the origin of the aorta, and bifurcation of aorta as well as the bifurcation angles of the abdominal aorta. The vertebral levels at which the abdominal aorta started and bifurcated were determined. The lengths and external diameters of the common iliac arteries, diameters of the internal and external iliac arteries, and lengths of the external iliac arteries were measured. The vertebral levels of bifurcation of the common iliac arteries were determined.

The fetal abdominal aorta lay in the midline, in front of the vertebral column. The mean bifurcation angle of the abdominal aorta was greater than adults in the third trimester and at full term. The lengths and diameters of the abdominal aorta and the iliac arteries increased with gestational age, and significant positive correlations were found. There were no sex or laterality differences in either parameter. External diameter of the internal iliac artery was larger than that of the external iliac artery. Bifurcation of the abdominal aorta to the common iliac arteries was more inferior compared to the adults, and these levels rose with gestational age.

The morphometric parameters and location of the fetal abdominal aorta and the iliac arteries were determined by the present study. We conclude that the abdominal aorta lay in the midsagittal plane. The bifurcation level of the abdominal aorta arose with gestational age and at full term, and reaches to the same level as adults. In the early fetal period, the bifurcation level of the common iliac artery was more inferior compared to the adults, and they reach the adult positions around full term. The diameter of the internal iliac artery was nearly one and a half times larger than the external iliac artery. The findings of this study would be present, detailed information about the development of the abdominal aorta and the iliac arteries; this will also contribute to radiological (ultrasound and MR) studies in the intrauterine period.