PCOS
Meaning of PCOS: Despite the name, the defining problem is hormonal rather than the small follicles that scans pick up, and it reaches well beyond the ovaries.
Definition of PCOS
PCOS stands for polycystic ovary syndrome, a common hormone and metabolic condition in which ovulation becomes irregular or stops. Its usual features are irregular or absent menstrual periods, raised levels of androgens such as testosterone, and ovaries holding many small fluid-filled follicles. Androgen excess can produce extra facial or body hair, acne and thinning scalp hair.
What is going on hormonally?
In a typical menstrual cycle, one follicle matures each month, releases an egg and leaves the rest to break down. In PCOS that selection stalls. Many follicles begin to develop and none is released, so they remain as the small fluid-filled sacs that show on an ultrasound scan. They are immature follicles rather than true cysts, which is why the name is misleading. Meanwhile the ovaries produce more androgens than usual. Without ovulation there is no progesterone in the second half of the cycle, so periods become unpredictable or stop, and the lining of the uterus is exposed to estrogen without progesterone to balance it.
Where does insulin resistance fit in?
Many people with PCOS have insulin resistance, meaning the body's cells respond poorly to insulin and the pancreas compensates by releasing more. High circulating insulin pushes the ovaries to make additional androgens and lowers a blood protein that normally binds testosterone, leaving more of it active. The result is a loop in which the metabolic problem worsens the hormonal one. This is why PCOS is associated over the long term with a higher chance of type 2 diabetes, high blood sugar in pregnancy, raised blood pressure and unfavorable blood lipids. Insulin resistance occurs in people of any body size with the condition, though it is more frequent in those carrying extra weight.
How is the diagnosis reached?
| Feature assessed | How it is looked for |
|---|---|
| Irregular or absent ovulation | Menstrual history |
| Androgen excess | Physical signs, blood hormone testing, or both |
| Many small ovarian follicles | Ultrasound of the ovaries |
Widely used criteria require more than one of these features to be present, and they require other conditions that mimic the picture, including thyroid and adrenal disorders and raised prolactin, to be excluded first. No single test confirms PCOS, and the presentation ranges from mild to severe.
Also known as
Used in a sentence
The patient was evaluated for PCOS after reporting irregular periods and laboratory findings of elevated androgen levels.
Good to know
The small follicles seen on an ovarian scan are not cysts requiring removal, and that imaging finding alone does not establish PCOS without the menstrual or androgen features and the exclusion of conditions that resemble it.