Histomorphometric parameters of normal full term placenta of Sudanese women.

The aim of the study was to provide values for morphometric parameters of histological components of normally delivered full term placentas of Sudanese women and compare them with reported parameters for other ethnic groups. A total of 200 histological sections, stained with hematoxylin and eosin and trichrome stains were used to give a final sample of 1000 fields saved as PowerPoint images for histomorphometry. A systematic random sampling procedure was adopted to ensure the optimum sample size that keeps the percentage error below 5% for the volume estimates. Standard stereological methods of point-counting and intersection-counting were applied to the microscopic fields to determine the volumes of placental components and surface area of fetal-maternal interface. The morphometric parameters showed no variations either between the placentas or between central and peripheral regions. The placental villi and the intervillus space occupied 65% and 35% of placental volume respectively with mean absolute values of 318 cm(3) and 169 cm(3). The mean absolute volume of the intervillus space was less than that of other ethnic groups by 8.67% but was significantly larger than that of the fetal capillaries which measured 41.2 cm(3). The ratio of the absolute volume of the intervillus space to the volume of the fetal blood capillaries was 4:1 in both Sudanese and other ethnic groups. In the placental villi the fetal connective tissue together with the contained blood vessels larger than capillaries occupied 88% of the villus volume. The mean surface area of the fetal-maternal interface of the placental villi (syncytiotrophoblast) was 12.59 M(2).