Since the proper growth and development of both embryo and fetus are influenced by the proper growth and development of the placenta, so any changes in the normal developmental sequence, hence, morphology and functionality of the placenta may lead to an adverse outcome on the pregnancy and to harmful effects to the mother and child. Ten placentas, with an eccentric umbilical cord insertion, from a full term healthy pregnant women who undergo normal vaginal delivery were used. Each placenta was divided into ten sections which reflect the main three zones; zone –I represents the large distance restricted between the eccentric cord insertion and the periphery, zone –II which is the zone of the cord insertion itself and zone –III which represents the small distance restricted between the cord insertion and the periphery.
These samples were prepared and examined histologically; using H&E stain to estimate the morphometric parameters included in this study, which were considered to be representative for the placental function and development; these include: the number, the diameter, the perimeter and the total perimeter of the villi in addition to the number of syncytial cells and of the blood vessels of the villi and histochemically; using Alcian blue and PAS stains for detection of the carbohydrate histochemical reactivity of these placental tissues. The morphometric data obtained from these sections showed that zone –I have a high mean number of the villi, total perimeter, mean number of syncytial cells and mean number of blood vessels of the villi with a low diameter and perimeter of the villi as compared IX with zone –III, and these differences were statistically significant with the exception of the diameter of the villi. The histochemical reactivity showed that placental tissues stained by Alcian blue / PAS sequence reveal darker Alcian blue color uptake and reactivity, at pH 2.5, in sections of zone –I compared to those of zone –III, while PAS stain shows the same color uptake and reactivity in sections of all zones. Concerning the results obtained from this study, bearing in mind the differences in the morphometric data and the carbohydrate histochemical reactivity, that zone –I could be considered to be of better exchange function than zone –III.