The clinical resolution of OHSS occurs as hCG diminishes. hCG (human chorionic gonadotropin) is an hormone used to detect if a woman is pregnant. This hormone’s synthesis occurs within the brain of both men and women with different purposes:
- Men: it is involved in the production of testosterone in the testes.
- Women: it induces egg maturity.
In addition, hCG is also produced within a part of the placenta (syncytiotrophoblast) and the embryo; hence the increase of its levels in pregnant women.
During pregnancy, hCG prevents the disintegration of the corpus luteum in the ovary and maintains the production of progesterone, the latter being extremely important during pregnancy. Furthermore, it is involved in the immune tolerant phase of pregnancy.
Since hCG secretion starts 6 days after you get pregnant, it can be used as a marker of pregnancy. This is the reason why, if pregnancy has occurred, the OHSS can be extended, which may worsen the patient’s clinical picture. Late OHSS may last 60-70 days.