Getting pregnant with PMOS (previously called PCOS)

Polyendocrine metabolic ovarian syndrome (PMOS) is the new name for polycystic ovary syndrome (PCOS). The NHS started using it in 2026. If you have PMOS, you may find it takes longer to get pregnant, but it is still possible to conceive naturally, and fertility treatment helps many people.

Why the new name?

The old name focused on cysts, but cysts aren’t a key feature of the condition, and the name may have delayed some people’s diagnosis. The new name reflects that it affects hormones and metabolism, not just the ovaries. You’ll see both names for a while, and it’s the same condition.

How PMOS affects fertility

With PMOS, your ovaries don’t always release an egg each month. That’s usually why it can be harder to get pregnant. It often shows up as irregular periods or long gaps between periods. Symptoms vary a lot: some people have mild symptoms, some have severe ones, and some have none.

You can still get pregnant even if your periods are irregular or you don’t have them, because you may ovulate some months. So if you don’t want to get pregnant yet, you still need contraception.

See your GP early

If you have PMOS, or think you might, it’s a good idea to see your GP as soon as you start trying, rather than waiting a year. They can check your hormones and whether you’re ovulating, and refer you to a fertility clinic if needed. If you’re on hormonal contraception, the bleeds you have on it aren’t true periods, so you might not know your cycle wasn’t regular until you stop.

Things that can help

Weight, if you’re overweight

If you’re overweight, losing weight may help you ovulate more regularly. Even losing 5% of your starting weight can make a significant difference to PMOS symptoms. Your GP can also talk to you about weight loss medicines.

Weight loss injections must not be used while you’re trying to get pregnant or while pregnant, and you may need to stop them up to 2 months before you start trying, so plan this with your GP. Some can also make the pill less effective.

Healthy eating and exercise

Being a healthy weight may improve symptoms and help you ovulate more regularly. A healthy, balanced diet and regular exercise both help. No particular type of diet has been shown to work better than another for PMOS, so choose one you can stick to.

Tracking ovulation

Ovulation tests can be harder to use if your cycles are irregular. Our guide to tracking ovulation compares the options. Your GP can also arrange a blood test to check whether you’re ovulating.

Fertility treatments for PMOS

Tablets to help you ovulate

Clomifene encourages your ovaries to release an egg. It isn’t usually given for more than 6 months.
Letrozole is another tablet that helps you ovulate. It’s licensed as a breast cancer medicine, so it’s used ‘off-label’ (outside its licence) for this. An international guideline from 2023 recommends it as the first choice for people with PMOS who aren’t ovulating, and NICE has proposed the same in its draft PMOS guideline, due in late 2026. In a large study of 750 women, 27.5% of those given letrozole had a baby, compared with 19.1% of those given clomifene. Many NHS fertility clinics already offer it, so ask your specialist which tablet they recommend.
Metformin, a type 2 diabetes medicine, can help make your periods more regular.

Other treatments

Gonadotrophin injections stimulate the ovaries directly. They can cause more than one egg to ripen, which means a higher chance of twins or more, so you’ll have regular scans.
Laparoscopic ovarian drilling is keyhole surgery that uses heat or a laser to treat tissue on the ovaries, which can help them release eggs. It may be suggested if other treatments or lifestyle changes haven’t worked.
IVF may be offered if other treatments haven’t worked or there are other fertility issues.

Before you get pregnant

Take 400 micrograms of folic acid a day. If you also have diabetes, you need the higher 5mg dose, so ask your GP.
Take 10 micrograms of vitamin D a day.
Ask your GP to check your blood pressure and blood sugar, as PMOS raises the risk of type 2 diabetes and high blood pressure.

PMOS in pregnancy

PMOS can increase the risk of some pregnancy complications, including high blood pressure, pre-eclampsia, miscarriage and premature birth. Tell your midwife you have PMOS. You may be offered a glucose tolerance test to check for gestational diabetes, usually at 24 to 28 weeks, and some guidelines recommend an earlier test as well. Our Q&A on PCOS and pregnancy covers your baby’s growth and birth.

Support

Verity is a UK charity for people with PMOS, and the NHS also points to the British Fertility Society for information about fertility.

Questions people ask

Can you get pregnant naturally with PMOS?

Yes. Many people with PMOS conceive without treatment, though it may take longer. Because cases vary so much, there aren’t exact figures.

Is PMOS the same as PCOS?

Yes. PMOS is the new name for PCOS, adopted by the NHS in 2026. The condition and its treatments haven’t changed.

How long should I try before seeing a GP if I have PMOS?

You don’t need to wait. It’s a good idea to see your GP as soon as you start trying.

Do I need IVF if I have PMOS?

Usually not straight away. Most people start with lifestyle changes and tablets to help ovulation. IVF is an option if these don’t work.