PCOS (now also called PMOS) and your cycle

What PCOS is

Polycystic ovary syndrome (PCOS) is a hormone condition, not a disease of cysts. In PCOS, the ovaries often don't release an egg on a regular schedule, and the body tends to make more androgens (hormones like testosterone, which everyone has in some amount). Many people with PCOS also have insulin resistance, where the body needs more insulin to keep blood sugar steady, which can push androgen levels higher still.

The 'cysts' in the name are really small follicles: eggs that started developing but didn't get released. That's part of why the name has long been criticized. The NHS now uses the name polyendocrine metabolic ovarian syndrome (PMOS), which reflects that the condition affects hormones and metabolism across the body, not just the ovaries. You'll see both names for a while.

Common signs

• [Irregular periods](/symptoms/irregular-periods): cycles longer than 35 days, fewer than about eight periods a year, or periods that stop for months
• Excess hair growth on the face, chest, back or belly (hirsutism), or thinning hair on the scalp
• Acne or oily skin, often along the jaw and chin (see period acne), that's hard to shift
• Weight gain or finding it hard to lose weight, often around the middle
• Difficulty getting pregnant, because ovulation is irregular
• Tiredness, low mood or anxiety, which the NHS lists among the main symptoms
• Dark, velvety patches of skin on the neck or armpits (acanthosis nigricans), a sign of insulin resistance

Symptoms usually start around puberty and range from barely noticeable to severe. You don't have to have all of them, and you don't need to be overweight to have PCOS.

How PCOS is diagnosed

There's no single test. Most doctors use the Rotterdam criteria: PCOS is diagnosed when you have at least two of these three, once other causes have been ruled out:

Your doctor will usually also check things that can mimic PCOS, such as thyroid problems, high prolactin and pregnancy. In teenagers, doctors are careful: irregular cycles are normal in the first years after periods start, so they usually wait and watch. The NHS notes ultrasounds are only done if you're over 18.

What PCOS does to your cycle

In a typical cycle, one follicle grows, ovulates, and about two weeks later you get a period. In PCOS, follicles often start growing but stall, so ovulation is delayed or doesn't happen. Without ovulation there's no progesterone rise, and the lining of the uterus can build up for weeks or months before shedding, sometimes as a heavy, unpredictable bleed.

Going many months without a period isn't just inconvenient. A lining that builds up without regular shedding raises the long-term risk of endometrial problems, so doctors often recommend having a bleed at least every three to four months, with medication if needed. Our guide to tracking your cycle with PCOS goes deeper.

PCOS and mood

Anxiety and depression are more common in people with PCOS. Part of that may be hormonal and metabolic, and part is living with symptoms that affect how you look and feel, plus the uncertainty of irregular periods and fertility worries. If your mood is struggling, it's a real part of PCOS and worth raising with your doctor just as much as your periods.

What helps

• Movement and food: regular exercise and a balanced diet help insulin resistance and can make cycles more regular, even without weight loss. If you're overweight, losing even a small amount can restart ovulation for some people.
• The combined pill, progestogen-only pill or hormonal IUS to regulate bleeding and protect the lining.
• Metformin, a diabetes medicine that can help insulin resistance.
• Spironolactone or eflornithine cream for hair growth; skin treatments for acne.
• Fertility medicines such as letrozole or clomifene if you're trying to conceive.
• Regular check-ups: PCOS raises the risk of type 2 diabetes, high blood pressure and heart disease, so ask about blood sugar and blood pressure checks.
• Talking therapy if symptoms are affecting your mood or self-image.

Tracking with long or irregular cycles

Lulu learns from the cycles you log rather than assuming 28 days, so it can follow long and variable cycles. Logging mood and symptoms alongside makes it easier to see what changes when your cycle does.

When to see a doctor