We examined the gross and microscopic anatomy of placental tissues and umbilical cords from six species representing the three living families of the Suina. These species included, of the Suidae, the wart hog (Phacochoerus aethiopicus), the giant forest hog (Hylochoerus meinertzhageni), the domestic pig (Sus scrofa), and the banded pig of Malaysia (Sus scrofa vittatus); of the Tayassuidae, the white-lipped peccary (Tayassu pecari); of the Hippopotamidae, the hippopotamus (Hippopotamus amphibius) and the pigmy hippopotamus (Choeropsis liberiensis). All these species have a diffuse epitheliochorial placenta. The chorion is folded, and has on its surface rows of shallow ripples or villi, interrupted by round, oval or irregularly shaped areolae. Placental capillaries indent the epithelial layer covering the tops and sides of the interareolar villi, but not the columnar cell layer lying in the troughs between these villi or covering the areolae. Cuboidal cells cover the crests of the villi in the Suidae and Hippopotamidae, whereas in the Tayassuidae the epithelium is syncytial in appearance. The similarities in placental structure between the six species are more apparent than the differences. Suidae and Tayassuidae have smooth umbilical cords containing two arteries and one vein; those of the Hippopotamidae are pustule-encrusted and contain two arteries and two veins.
This study was conducted to determine the effect of ethnicity on maternal, placental and neonatal parameters. Maternal, placental, and the newborn parameters were corrected for gestational age. The male:female sex ratio was 1:1.03. One hundred and forty-four freshly delivered placentae from 55 Malaysian, 51 Chinese, and 38 Indian normal healthy patients were collected and standard stereological methods used to estimate the placental parameters. Pearson's correlation, Spearman's correlation and 1-way ANOVA were used to test significance of differences. Placental surface area, placental weight and placental volume of Indians were lower than Malays (P< 0.05). Placental weight correlated significantly with neonatal length (r=0.527), birthweight (r=0.665), head circumference (r=0.371) and booking weight (r=0.193) while placental volume correlated with neonatal length (r=0.588), birthweight (r=0.688), head circumference (r=0.384), parity (r=0.202) and booking weight (r=0.219) at P< 0.05. Indian babies weight and length were less than Chinese and Malay babies (P< 0.05) while booking weight of Indian mothers was less than those of Chinese mothers (P< 0.05). Even after being corrected for booking weight, placental parameters of Indian patients were still significantly less than Malays and Chinese (P< 0.05).
Placenta as a fetomaternal organ is a potential source of fetal as well as maternal stem cells. This present study describes novel properties of the cells isolated from the maternal part of term placenta membrane, the decidua basalis.