What is PCOS?
PCOS involves a ‘vicious cycle’ of hormone imbalance. Hormones are simply proteins produced in one organ that effect other parts of the body, and the main players in PCOS are GnRH, (Gonadotropin Releasing Hormone), FSH (Follicle Stimulating Hormone), LH (Luteinising Hormone), oestradiol (the most common estrogen), progesterone, testosterone and insulin. Early diagnosis of PCOS is important as it has been linked to an increased risk for developing Insulin Resistance (IR or Prediabetes – PD) and Type 2 Diabetes.
To understand PCOS, let’s first look at normal hormone balance. There are two areas in the brain that are vital to normal menstrual cycles with ovulation:
- The Hypothalamus Producing GnRH
- The pituitary to produce FSH to stimulate follicles in the ovary to grow and mature its egg, and LH to trigger ovulation.
GnRH directs the pituitary to send an appropriate balance of FSH and LH to the ovary, stimulating both male (androgen) and female (estrogen and progesterone) hormone production, as well as ovulation – don’t forget the eggs!
Following ovulation, the ovary produces large amounts of progesterone to prepare the uterine lining (endometrium) for pregnancy. These ovarian hormones tell the hypothalamus to decrease or increase signals to the pituitary to maintain appropriate hormone levels at the ovary, i.e., oestrogen feedbacks to reduce FSH.
In PCOS, the hypothalamus (think overbearing boss), sends continuous messages to the pituitary (think underappreciated employee), but the latter seems a bit too hypersensitive (from being underpaid) and responds by making too much LH (think spite). Through a delicate balance of these hormone signals, ovulation occurs, but in PCOS it’s a like a fire drill with no guidance. The pituitary sends higher levels of LH to the ovary, resulting in more androgens and sends lower signals of FSH, preventing follicle growth and ovulation.
All this LH work and not enough FSH play makes the ovary very dull!
This ovarian ‘androgen excess’ of testosterone has several effects:
- Blocks follicle development (ovulation)
- Excess hirsutism (male pattern hair in sex dependent areas)
- Makes a weaker oestrogen in the fat cells of the body, called oestrone
The more estrogen like hormones there are, the more FSH production is reduced, further preventing follicle development and ovulation. Without ovulation, progesterone levels remain very low. This combination of hormone imbalance brings about a buildup of the endometrium increasing the risk of abnormal bleeding and endometrial hyperplasia (a precancerous change).
To summarize, in PCOS, due to the hypothalamus and pituitary having internal human resource problems, the ovary and uterus are not happy campers and wish they could take their business elsewhere!