If you have polycystic ovary syndrome (PCOS), working out whether you might be pregnant can be tricky. Irregular periods mean a missed period doesn't tell you much, and some PCOS symptoms look a lot like early pregnancy.
The short answer: the most useful early signs are feeling sick, breast changes that feel different from usual, needing to pee more often and sudden tiredness. But the only way to know is a pregnancy test, done at least 3 weeks after you last had unprotected sex.
Get urgent help (A&E or NHS 111) if you might be pregnant and have pain low down on one side of your tummy, pain in the tip of your shoulder, vaginal bleeding, or feel faint or dizzy. These can be signs of an ectopic pregnancy.
Related: Can irregular periods cause infertility?
Why PCOS makes early pregnancy harder to spot
Many people with PCOS go weeks or months without a period. When your cycle is unpredictable, a late period doesn't carry the same meaning, so pregnancy can go unnoticed for longer. Some people only find out after other symptoms become obvious.
The hormone changes in PCOS can also cause bloating, tiredness, mood changes and sometimes breast discomfort, all of which can happen in early pregnancy too. That overlap makes it easy to dismiss real pregnancy symptoms as "just my PCOS", or to read too much into normal PCOS symptoms.
You may also see PCOS called polyendocrine metabolic ovarian syndrome (PMOS), a newer name the NHS has started to use.
Common early signs of pregnancy with PCOS
Breast tenderness
Your breasts may feel sore, heavy or more sensitive to touch. PCOS can cause some breast discomfort, but pregnancy tenderness is often stronger and doesn't come and go. It usually starts within the first few weeks as hormone levels rise.
Feeling sick
Nausea isn't a typical PCOS symptom, so it can be one of the more useful signs. Despite the name, morning sickness can happen at any time of day and may be set off by smells or certain foods. It often starts around 4 to 6 weeks of pregnancy.
Tiredness
Pregnancy tiredness can feel different from your usual PCOS tiredness: sudden, heavy and not helped by a good night's sleep. Rising progesterone in early pregnancy is a big part of this.
Needing to pee more often
You may need the toilet more often, including at night, sometimes even before a period would be due. If peeing hurts or burns, that's more likely to be a urine infection, which needs checking, especially if you could be pregnant.
Changes in taste and smell
Foods or drinks you normally enjoy, such as coffee, can suddenly seem off-putting, and you may crave others. Some people notice a metallic taste.
PCOS symptoms vs early pregnancy symptoms
| Symptom | Common with PCOS? | Common in early pregnancy? | How to tell |
|---|---|---|---|
| Missed or late period | Yes | Yes | Not reliable with PCOS; test 3 weeks after unprotected sex |
| Feeling sick | Not usually | Yes | One of the more useful signs if it's new for you |
| Sore or tender breasts | Sometimes | Yes | Pregnancy tenderness is often stronger and doesn't ease |
| Needing to pee more often | Not usually | Yes | New, without pain or burning |
| Tiredness | Yes | Yes | Pregnancy tiredness is often sudden and overwhelming |
| Bloating and cramps | Yes | Yes | Hard to tell apart; don't rely on these |
Cramping
Mild cramping can happen with PCOS at any point in your cycle, and also in early pregnancy. Some people notice light cramps or spotting around the time a fertilised egg implants, about 6 to 12 days after conception, but many don't. Cramping on its own isn't a reliable sign either way.
Bloating and weight changes
Both PCOS and early pregnancy can cause bloating and small weight changes, so these aren't useful signs on their own.
Mood changes
PCOS can affect mood, and so can pregnancy hormones. In pregnancy, you might find yourself tearful at adverts or irritable over small things. Like bloating, mood changes are hard to read on their own.
When to take a pregnancy test
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A home pregnancy test is accurate 3 weeks after you last had unprotected sex. If you don't have regular periods, use that rule rather than waiting for a missed period. If it's negative but you still have symptoms, test again a few days later with your first pee of the morning, when the pregnancy hormone (hCG) is most concentrated.
PCOS doesn't affect how pregnancy tests work, but irregular cycles make it easier to test too early. You may ovulate later than you expect, so hCG might not have built up to a level the test can pick up yet.
Blood tests aren't usually needed; a home test is reliable if you test at the right time. If you keep getting negative results but your period still hasn't come, or you have symptoms that worry you, speak to your GP. The NHS guide to doing a pregnancy test has more detail.
If your test is positive
- Folic acid: start taking folic acid straight away if you're not already. The usual dose is 400 micrograms a day until 12 weeks. Some women with PCOS, especially with a BMI of 30 or more, are advised a higher 5mg dose on prescription, so speak to your GP.
- Book in with a midwife: you can refer yourself or go through your GP, ideally before 10 weeks.
- Tell your GP or midwife you have PCOS: it can raise the chance of gestational diabetes, so you may be offered extra checks.
- Check your medicines: check any medicines you take with a pharmacist or GP before carrying on. Some treatments used for PCOS symptoms shouldn't be used in pregnancy, including spironolactone and eflornithine cream (Vaniqa) for facial hair. If you take metformin, don't stop it suddenly; ask your GP what to do.
Pregnancy with PCOS
Most people with PCOS have healthy pregnancies. PCOS does carry a slightly higher chance of some problems, such as gestational diabetes, high blood pressure and pre-eclampsia, which is why your midwife may suggest extra checks. Going to all your antenatal appointments, staying active and eating well all help.
Getting support
If you think you might be pregnant, a well-timed home test is the best first step. Your GP or midwife can support you once you have a result, and a pharmacist can check whether your current medicines are safe in pregnancy. The charity Verity offers support and information for people with PCOS.
PCOS and pregnancy FAQs
Can PCOS cause a false negative pregnancy test?
No. PCOS doesn't affect how pregnancy tests work. False negatives happen when you test too early, before there's enough pregnancy hormone to detect, and irregular cycles make it easier to test too early.
How soon can I test for pregnancy with irregular periods?
Do a test at least 3 weeks after you last had unprotected sex. If you don't have regular periods, use that rule rather than waiting for a missed period. If it's negative but you still think you could be pregnant, test again a few days later with your first pee of the morning.
Can you get pregnant with PCOS?
Yes. Many people with PCOS get pregnant naturally, although it can take longer because ovulation is less regular. If you've been trying for a year, or 6 months if you're 36 or over, see your GP. Treatments to help you ovulate can help.
Does PCOS make pregnancy symptoms worse?
Not usually. Early pregnancy symptoms are similar with or without PCOS. The difference is that some PCOS symptoms, such as bloating, mood changes and tiredness, can look like pregnancy symptoms, which makes them harder to read.
Should I keep taking metformin if I'm pregnant?
Don't stop or start metformin without advice. Speak to your GP or the doctor who prescribed it as soon as you get a positive test. They'll tell you whether to carry on, depending on why you take it.
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