The origin of IFN-γ is not clearly identified and could be the natural killer cells of the uterus, the placental dendritic cells modulating responses of T helper cells, alterations in synthesis of or response to regulatory molecules, or changes in the function of regulatory T cells in pregnancy. Aberrant immune responses promoting pre-eclampsia may also be due to an altered fetal allorecognition or to inflammatory triggers. It has been documented that fetal cells such as fetal erythroblasts as well as cell-free fetal DNA are increased in the maternal circulation in women who develop pre-eclampsia. These findings have given rise to the hypothesis that pre-eclampsia is a disease process by which a placental lesion such as hypoxia allows increased fetal material into the maternal circulation, that in turn leads to an immune response and endothelial damage, and that ultimately results in pre-eclampsia and eclampsia. One hypothesis for vulnerability to pre-eclampsia is the maternal-fetal conflict between the maternal organism and fetus. After the first trimester trophoblasts enter the spiral arteries of the mother to alter the spiral arteries and thereby gain more access to maternal nutrients. Occasionally there is impaired trophoblast invasion that results in inadequate alterations to the uterine spiral arteries. It is hypothesized that the developing embryo releases biochemical signals that result in the woman developing hypertension and pre-eclampsia so that the fetus can benefit from a greater amount of maternal circulation of nutrients due to increased blood flow to the impaired placenta.
Pubertal development is regulated by the hypothalamic-pituitary-gonadal (HPG) axis. Tanner staging ranges from 1 through 5 (with 5 being the most developed).With regards to pubic hair development, the scale goes as follows: Stage 1-no hair; 2-downy hair; 3-scant terminal hair; 4-terminal hair overlying the pubic triangle; 5-terminal hair extending to the thigh. With regards to male genitalia development, the scale goes as follows: 1-testes at the same size and proportion of early childhood; 2-enlargement of the scrotum/change in texture of scrotal skin; 3-growth of the penis length-wise; 4-growth of the penis in terms of length and circumference; 5-adult-sized genitalia. With regards to female breast development, the scale is as follows: 1-no palpable gland tissue; 2-palpable breast bud under areola; 3-breast tissue palpable outside of areola; 4-areola elevated above breast contour; 5-areolar mound recedes into single breast contour. The average age in which both males and females reach Tanner stage 5 of pubertal development is around 15–16. Neurological development
There are significant neurological changes that are expressed during preadolescence. White matter refers to the region of the nervous system corresponding to neuronal axons, which form fibers that convey information across different regions of the brain. In contrast, grey matter refers to the region of the nervous system corresponding to neuronal cell bodies, which process and relay neuronal signals. White matter volume increases at a relatively linear rate of about 12% from ages 4 through 22, specifically focused in the frontal, parietal, and occipital lobes.