Human Chorionic Gonadotropin

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•  hCG stimulates the ovary to secrete progesterone during early pregnancy

When a blastocyst becomes implanted in the endometrial lining it begins to secrete human chorionic gonadotropin (hCG)

  • hCG promotes the maintenance of the corpus luteum within the ovary and prevents its degeneration

As a consequence of this, the corpus luteum survives and continues to produce both oestrogen and progesterone

  • Oestrogen inhibits FSH and LH production by the pituitary gland, preventing the release of more eggs from the ovaries
  • Progesterone also functions to maintain the endometrium (which is nourishing the embryo) and thicken the cervix

The levels of hCG are maintained for roughly 8 – 10 weeks while the placenta is being developed

  • After this time, the placenta becomes responsible for progesterone secretion and nourishing the embryo
  • At this point the corpus luteum is no longer required and begins to degenerate as hCG levels drop

The Role of hCG and Progesterone During Early Pregnancy