Understanding:
• 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
