Quantitative Gonadotropin-Releasing Hormone: DISCUSSION(2)
This enigmatic process is the result of an embryonic-maternal dialogue, in which the embryo and the endometrium induce changes in each other to promote receptivity. Growth factors and cytokines are secreted by the developing blastocyst to enhance uterine receptivity, directly by influencing the endometrial epithelial cells to undergo cellular changes such as down-regulation of cell polarity, or indirectly by stimulation of ovarian steroidogenesis through hCG, until placental progesterone production is sufficient to maintain the continuing pregnancy. buy yasmin online
After adhesion of the embryonic pole of the human blastocyst to the endometrial epithelial surface, trophoblastic differentiation into cytotrophoblast and syncytiotrophoblast develops as the trophoblast invades the stromal endometrium. Human CG secretion rises in a logarithmic fashion from 6 days after conception until the wk 10-11 after the last menstrual period, at which time the level peaks. This is followed by a decline to a nadir reached about wk 18 and remaining constant until term. One of the primary functions of hCG during the early steps of pregnancy is to stimulate progesterone production by the corpus luteum as well as to enhance uterine receptivity, since progesterone has immunosuppressive properties that potentially prevent maternal rejection.