What it is
PMOS is a common hormonal condition affecting the ovaries, periods, fertility, skin and metabolism. It affects about 1 in 8 women of reproductive age. It was previously called PCOS, polycystic ovary syndrome. That name is misleading: the ovaries hold many small follicles, not harmful cysts. There are three threads: disrupted ovulation, raised androgen hormones such as testosterone, and underlying insulin resistance.
Symptoms to look out for
- Irregular, infrequent or absent periods
- Difficulty getting pregnant
- Acne, excess facial or body hair, or thinning scalp hair
- Weight gain, especially around the waist
- Dark skin patches in the armpits or neck, and skin tags
What causes it
Insulin resistance is central: the body needs more insulin than usual, so insulin levels rise. High insulin pushes the ovaries to make more androgens and disrupts ovulation. There is a strong family link. PMOS occurs in people of all body sizes, and poor sleep, stress and some medicines can make it worse.
Improving insulin sensitivity can break the cycle
High insulin makes the ovaries produce more androgens, and promotes weight gain around the waist, which raises insulin further. Reducing insulin resistance breaks this loop: periods often become more regular, ovulation and fertility improve, and skin and hair symptoms ease. This works for lean women too, where the focus is insulin sensitivity rather than weight loss.
What you can do
- Food. Cut sugary drinks and ultra-processed snacks. Build meals with plenty of protein and non-starchy vegetables, and keep starchy carbohydrate to smaller amounts. Losing around 5 to 10% of body weight can restore ovulation.
- Movement. At least 150 minutes a week of moderate activity such as brisk walking, plus 2 to 3 resistance sessions.
- Sleep and stress. Aim for 7 to 9 hours of sleep, and keep a regular schedule. Brief daily relaxation helps lower stress.
- Supplements. Myo-inositol has evidence for improving insulin sensitivity and ovulation. Check any supplement with your clinician.
Medicines
Metformin improves insulin sensitivity and can help periods and ovulation. The combined pill regulates periods and reduces androgen symptoms when not trying to conceive. Anti-androgen medicines help hair and acne but must not be used in pregnancy. All need medical supervision.
When to get help
- See a doctor about irregular or absent periods, troublesome acne or excess hair, or difficulty getting pregnant.
- Ask for a check of your metabolic health: blood sugar (HbA1c), blood fats and blood pressure. This is usually done every year.
- If you are planning a pregnancy, ask for a pre-conception review, as some medicines must be stopped first.