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Anovulation: What It Is, Why It Happens and What Helps

You've been tracking your cycle and something feels off. Periods that turn up when they feel like it. Ovulation sticks that never seem to peak. Months of trying to conceive without success. Anovulation might be the missing piece.

Not the panic-inducing version the internet loves. The "let's actually understand what's happening in your body" version. Anovulation simply means a cycle where your ovaries don't release an egg. It sounds simple, but it gets tangled in fear-based content and medical jargon fast, so let's slow down.

You're not imagining it. Your body is trying to tell you something, and the guidelines have changed recently too: NICE replaced its main fertility guideline in March 2026 [1], and PCOS has been renamed PMOS (polyendocrine metabolic ovarian syndrome), so we use both names here. Your diagnosis is a starting point, not a verdict.

This is what I wish someone had told me: how to spot the signs, what causes anovulation, which tests are worth asking for, and what actually helps. If your cycles are all over the place, our guide to irregular periods and PMOS is a good companion read, and our guide to PMOS blood tests covers what to request.

A woman in a cream jumper sits at a wooden kitchen table by a sunlit window, writing dates in a cycle diary beside a mug of tea, with a wall calendar behind her

In this guide:

What Is Anovulation?

In short: Anovulation is a cycle where no egg is released. You can still bleed, so it often goes unnoticed for years, even when it matters for fertility.

Anovulation is a menstrual cycle in which your ovaries don't release an egg. It can happen occasionally in anyone, or repeatedly as part of an underlying hormonal condition.

Here's what surprises a lot of women: you can still bleed without ovulating. In an anovulatory cycle, there's no corpus luteum (the structure that forms after an egg is released) and so no progesterone. Oestrogen keeps stimulating the womb lining, and the lining eventually breaks down and sheds unpredictably [2, 3]. That bleed can look almost identical to a period, which is why a bleed isn't proof you ovulated.

No ovulation also means no progesterone, the hormone that comes from the second half of a normal cycle (the luteal phase). That's why anovulation matters beyond fertility: it explains why cycles feel erratic, and why long gaps between periods are worth investigating.

Occasional anovulation is normal at certain life stages. In the first years after periods start, anovulatory cycles are common, and intermittent anovulation can begin years before menopause [3]. Repeated anovulation across many cycles is a different picture, and worth a conversation with your GP.

How Common Is Anovulation?

In short: There is no single reliable figure. Ovulation problems are involved in roughly a quarter of fertility difficulties, and PMOS is the most common cause.

You'll often see "1 in 10 women have anovulation". We couldn't trace that to NICE, the NHS or the NIH, so we don't use it. What the sources do say is below.

Source What it says Worth knowing
NICE (2013 guideline context) Ovulatory disorders account for about 25% of infertility causes, and infertility affects about 1 in 7 couples [4]. That guideline has since been replaced by NG257 [1], which doesn't restate the percentages. Treat this as a rough guide.
NHS "Lack of regular ovulation" is among the female causes of infertility, and in about a quarter of cases no cause is found [5]. Fertility problems often involve both partners.
American Society for Reproductive Medicine (2021) Occasional anovulation in women with regular cycles is estimated at 1 to 14% [6]. This is a wide range because studies differ.
WHO and NICE (PMOS) About 10 to 13% of women have PMOS (WHO), or around 1 in 8 (NICE draft) [7, 8]. WHO calls it the most common cause of anovulation [7]. Having PMOS isn't the same as having anovulation, because some women ovulate irregularly.

The practical point: if your cycles are irregular or absent, anovulation is common enough to take seriously and treatable enough to be worth chasing.

What Are the Signs of Anovulation?

In short: The clearest sign is irregular or missing periods. Home signs like mucus or ovulation sticks can mislead, and a blood test confirms it.

Because anovulatory cycles can look like regular ones, spotting anovulation takes some cycle literacy. But not every popular sign is equally reliable. Here's an honest ranking.

Sign How reliable is it? What to do
Irregular or absent periods The clearest clue. The NHS counts cycles shorter than 21 days or longer than 35 days as irregular [9]. Track dates for a few months and see your GP if the pattern holds.
Regular monthly cycles NICE says regular monthly cycles mean you're likely to be ovulating, though it still offers a progesterone test during fertility investigations [1]. Regular cycles are reassuring but not a guarantee.
Ovulation sticks (LH tests) Accuracy varies, and in PMOS persistently raised LH can cause false positives [6]. Treat a positive stick as a hint, not proof.
Basal body temperature charts NICE says not to use them to confirm ovulation because they don't reliably predict it [1]. Skip them if they're stressing you out.
Cervical mucus, mid-cycle pain, PMS-type symptoms Popular, but we couldn't find guideline support for using these to diagnose anovulation. Fine to notice, but don't rely on them.

None of these signs, alone, confirms anovulation. A pattern across several cycles is worth taking to a GP, who can arrange a proper test. If you want help tracking, see our review of cycle and ovulation tracking apps and devices.

What Causes Anovulation?

In short: Common causes include PMOS (PCOS), thyroid problems, high prolactin, low energy intake or heavy exercise, weight changes and some medicines.

There's no single cause. Here are the main ones, so you know what your GP may be looking for.

PMOS (PCOS). The WHO describes PCOS (now PMOS) as the most common cause of anovulation [7]. Researchers describe how insulin resistance and raised insulin can push the ovaries to make more androgens such as testosterone, which interferes with follicles maturing and releasing an egg [10]. Our guide to PMOS and insulin resistance goes deeper.

Thyroid problems. A major review found that overactive and underactive thyroid can both cause menstrual disturbances, with hypothyroidism linked mainly to infrequent periods (oligomenorrhoea) [11]. The NHS also lists thyroid problems among the causes of irregular periods [9].

High prolactin. Prolactin is the hormone behind breast milk production. Raised levels outside pregnancy and breastfeeding can switch off ovulation. Causes include a benign pituitary growth (prolactinoma), an underactive thyroid, and some medicines, including certain antipsychotics and antidepressants and some blood pressure medicines such as verapamil and methyldopa [12]. Never stop a medicine without speaking to your prescriber.

Low energy intake, heavy exercise or stress (functional hypothalamic amenorrhoea). When the brain senses too little fuel for the energy you use, it can turn down the signals that drive ovulation. The Endocrine Society guideline names weight loss, vigorous exercise and psychological stress as the triggers, with energy deficit as the key mechanism, and says it can only be diagnosed after other causes are excluded [13]. Everyday stress is less clear. In one cohort of 259 healthy women, higher daily stress was linked to more anovulatory cycles, but that's an association, not proof [14]. Most of the evidence that stress hormones suppress the reproductive axis comes from animal experiments [15]. So stress is rarely the whole story.

Weight. NICE says a BMI of 30 or over is likely to make conception take longer, and that for a BMI under 18.5 with irregular or absent periods, gaining weight is likely to improve your chance of conceiving [1]. In PMOS, abdominal excess weight is linked with insulin resistance and androgen excess, which can contribute to anovulation [16]. This isn't about a number on the scale, and it isn't a reason to be blamed.

Medicines and the pill. Hormonal contraception stops ovulation by design, and some other medicines can affect cycles through prolactin (see above). After stopping the pill, the NHS says fertility usually returns to previous levels after about a month, and that it can take up to three months for your natural cycle to get going [17]. The NHS advises seeing a GP if you've missed three periods in a row [18]. The pill can also mask irregular cycles you had before, so it's worth mentioning if they were a problem.

Premature ovarian insufficiency and perimenopause. If periods become irregular or stop before 40, ask about premature ovarian insufficiency, which is menopause before the age of 40 [19]. In your 40s, irregular cycles with anovulation are an expected part of perimenopause [9].

How Is Anovulation Diagnosed?

In short: A GP starts with your cycle history, then may use a mid-luteal progesterone test and hormone tests. AMH shows egg reserve, not ovulation.

There's no single test that tells the whole story. Here's what a work-up often involves, and what the guidance actually says.

Step What the guidance says What to ask
Cycle history NICE says to ask about how often your periods come and how regular they are [1]. A diary of dates helps. "Can I show you my cycle diary?"
Mid-luteal progesterone blood test NICE says to offer it in the middle of the second half of your cycle (day 21 of a 28-day cycle), later in longer cycles, and repeated weekly if cycles are much longer [1]. Many UK labs treat 30 nmol/L or above as good evidence you ovulated; lower or in-between results may mean the test was mistimed [20]. "When should the test be timed for my cycle length?"
Hormone tests NICE suggests FSH and LH for irregular cycles, and prolactin and thyroid tests where indicated [1]. The draft PMOS guideline also lists TSH, prolactin, oestradiol, LH and FSH to rule out other causes of irregular or absent cycles, and testosterone tests if PMOS is suspected [8]. "Have other causes been ruled out?"
AMH NICE says not to use AMH to predict a pregnancy through natural conception [1]. For PMOS, the draft says to use either an ultrasound or AMH to assess the ovaries, not both [8]. "What is this test for?"
Fasting insulin The 2023 international guideline says insulin assays are not recommended in routine care [21]. "What will my glucose results tell us?"

A few notes. Test timing matters more than most people realise: a progesterone test taken at the wrong time can look "low" in someone who did ovulate. NICE gives no nmol/L cut-off in its recommendations, so your result is read against your lab's own range [20].

An endometrial biopsy isn't part of a standard fertility work-up. The American Society for Reproductive Medicine says it's no longer recommended for routine infertility evaluation [6]. Doctors use biopsies in specific cases of abnormal bleeding, so don't expect one unless you have those risk factors.

When to see your GP. The NHS advises seeing a GP if you haven't conceived after a year of trying, and sooner if you're 36 or over or already know you may have a fertility problem [5]. If you have irregular or absent periods and want a baby, don't wait for the year to pass. Our guide to how to know if you have PMOS has more on what to say at the appointment.

Can Anovulation Be Treated?

In short: Yes. Treatment depends on the cause, from thyroid or prolactin medicines to lifestyle support and ovulation induction with letrozole.

It depends entirely on what's driving it, which is why diagnosis matters so much.

If it's thyroid or prolactin related, treating the underlying problem often restores ovulation. NICE says to offer cabergoline to treat ovulatory disorders due to hyperprolactinaemia [1], and a Royal Berkshire NHS leaflet says prolactin often falls to normal within weeks and that periods and fertility usually return in most cases [22].

If it's functional hypothalamic amenorrhoea, the first step is correcting the energy imbalance: eating enough, easing off intense exercise and getting support for stress or anxiety. The Endocrine Society also suggests cognitive behavioural therapy, and advises against using the pill just to restore periods [13]. It gives no fixed timeline, and says the longer the problem has lasted, the longer recovery tends to take [13].

If it's PMOS, the evidence for lifestyle changes is modest. A Cochrane review of 15 trials in 498 women found low-quality evidence that lifestyle changes may improve weight and the free androgen index, and no trial reported on menstrual regularity [23]. A systematic review of exercise found improvements in ovulation, insulin resistance and weight with aerobic and/or resistance exercise, but the studies varied a lot and the authors said conclusive results remain elusive [24]. One trial of a low-glycaemic-index diet found more women had improved menstrual cycles, though many dropped out [25]. NICE's draft says weight loss may restore ovulation where excess weight is a factor, and that no type of exercise has been shown to be better than another [8].

Ovulation induction. NICE's draft PMOS guideline says to offer letrozole to adults with PMOS who have anovulatory infertility and no other infertility factors, and to use clomifene (with or without metformin) if letrozole isn't suitable [8]. The 2023 international guideline also puts letrozole first [21]. In a large US trial in PCOS, live birth happened in 27.5% of women on letrozole versus 19.1% on clomiphene [26]. In the UK, letrozole is used off-label for fertility, so your specialist will explain this [27]. NHS trust leaflets quote that around 70 in 100 women ovulate on clomifene and about 40 in 100 conceive, with twins more likely, so treatment is usually limited to six cycles [28, 8].

Other options. If tablets don't work, the draft guideline lists gonadotrophin injections, laparoscopic ovarian diathermy (a keyhole procedure) and IVF, and says not to deny ovulation induction on BMI alone if BMI is under 40 [8].

What about inositol? The draft NICE guideline advises that inositol is not effective for fertility problems in people with PMOS [8], and a 2024 systematic review found the evidence supporting inositol in PCOS limited and inconclusive [29]. We say that plainly because we make inositol supplements. Treat them as an optional extra to discuss with your GP, never a substitute for the options above.

Can You Get Pregnant If You're Not Ovulating?

In short: Not without ovulating. But many women with PMOS ovulate irregularly, and treatment helps many. Folic acid and an early chat with your GP are sensible.

To conceive, you need to ovulate. But anovulation isn't always "never". Many women with PMOS ovulate irregularly, so pregnancy can happen naturally, and NICE's draft says it's often possible to conceive with or without medical assistance [8]. It's a symptom, not a verdict.

A few practical things. The NHS advises taking 400 micrograms of folic acid daily from before you start trying until 12 weeks of pregnancy, with a higher prescribed dose for some women, for example those with diabetes or on certain medicines [30]. Speak to your GP or pharmacist about which applies to you. NICE's guidance on weight, smoking and alcohol is also worth reading [1]. And keep your GP in the loop early, because earlier investigation means more options.

Where Does MyOva Fit In?

In short: MyOva makes food supplements, not treatments. They can't restore ovulation, and they're an optional extra to discuss with your GP.

MyOva makes Myoplus and Preconception, so you deserve the straight version. Neither is a treatment for anovulation, and neither is shown to help you ovulate. As above, the draft NICE guideline says inositol isn't effective for fertility problems, and the evidence is limited and inconclusive [8, 29].

Myoplus provides 4000 mg of myo-inositol a day with chromium, folate and vitamin B6. Chromium contributes to the maintenance of normal blood glucose levels, folate contributes to normal psychological function and to a reduction of tiredness and fatigue, and vitamin B6 contributes to the regulation of hormonal activity.

MyOva Myoplus Myo-Inositol supplement
Daily Food Supplement
Myoplus Myo-Inositol

4000 mg myo-inositol a day with chromium, which contributes to the maintenance of normal blood glucose levels, plus vitamin B6 and folate.

Preconception is a daily formula for people preparing for pregnancy. It provides 2000 mg of myo-inositol with folate, vitamin D3, zinc and vitamin B6, plus a wider range of vitamins and minerals. Zinc contributes to normal fertility and reproduction, folate contributes to maternal tissue growth during pregnancy, and vitamin B6 contributes to the regulation of hormonal activity. Check the folate amount on the label against the NHS advice above.

MyOva Preconception supplement
Daily Food Supplement
Preconception

2000 mg myo-inositol with folate, vitamin D3 and zinc, which contributes to normal fertility and reproduction, plus vitamin B6 and a broad vitamin and mineral range.

Safety first. Speak to your GP or pharmacist before taking any supplement if you take other medicines, if you're pregnant or breastfeeding, or if you're trying to conceive. Don't combine supplements without checking the product guidance, so you don't double up on nutrients. Food supplements shouldn't replace a varied diet or medical treatment.

Infographic titled Anovulation: What to Know and Ask, with five points: a bleed is not proof of ovulation, regular cycles usually mean you are ovulating, ask your GP about a progesterone blood test timed about 7 days before your next period, possible causes include PMOS (PCOS), thyroid, prolactin, low energy intake and some medicines, and treatment depends on the cause

Frequently Asked Questions

What does an anovulatory cycle feel like?

Often, nothing obvious. You may still bleed, which is why many women don't notice. Clues include irregular or missing periods and ovulation sticks that never clearly peak, but home signs aren't reliable proof, so ask your GP about a progesterone blood test [1, 6].

Can stress cause anovulation?

Sometimes. Severe stress combined with under-eating or heavy exercise can cause functional hypothalamic amenorrhoea. In everyday life the link is weaker: one cohort found higher daily stress was associated with more anovulatory cycles, but that doesn't prove cause [13, 14].

Does coming off the pill cause anovulation?

Not by itself. The NHS says fertility usually returns to previous levels after about a month, and it can take up to three months for your natural cycle to get going. See a GP if you've missed three periods in a row [17, 18].

How long does it take to restore ovulation?

It depends on the cause, and we couldn't find a reliable timeline. Thyroid and prolactin causes may respond within weeks to months once treated, while recovery from hypothalamic amenorrhoea varies widely [22, 13].

Is anovulation the same as PMOS (PCOS)?

No. PMOS is the most common cause of anovulation, but there are others, such as thyroid problems, high prolactin and low energy availability. And not everyone with PMOS has complete anovulation, because some ovulate irregularly [7].

The Bottom Line

Anovulation means no egg released. You can still bleed, so a bleed isn't proof of ovulation, and home signs can mislead. A GP can arrange a properly timed progesterone blood test and look for causes such as PMOS, thyroid problems, high prolactin or low energy intake. Most causes are treatable.

Hormonal literacy isn't complicated, it's just rarely taught. Start with one thing: track your cycle dates for a few months, then take them to your GP and ask what's causing the pattern. Your diagnosis is a starting point, not a verdict.

Related Reading

This article is for educational purposes only and does not constitute medical advice. Guidance details are accurate to the sources cited at the time of writing, and NICE's PMOS guideline is still in draft. MyOva products are food supplements, not medicines, and are not intended to diagnose, treat, cure or prevent any disease. If you think you may not be ovulating, or your cycles are changing, speak to your GP or a qualified healthcare professional before making changes to your treatment or supplements.

References

  1. National Institute for Health and Care Excellence. Fertility problems: assessment and treatment. NICE guideline NG257. Published 31 March 2026 (replaces CG156). https://www.nice.org.uk/guidance/ng257
  2. Hickey M, Higham JM, Fraser I. Progestogens with or without oestrogen for irregular uterine bleeding associated with anovulation. Cochrane Database Syst Rev. 2012;(9):CD001895.
  3. Sweet MG, Schmidt-Dalton TA, Weiss PM, Madsen KP. Evaluation and management of abnormal uterine bleeding in premenopausal women. Am Fam Physician. 2012;85(1):35-43.
  4. National Institute for Health and Care Excellence. Fertility problems: assessment and treatment. Clinical guideline CG156. 2013 (since replaced by NG257).
  5. NHS. Infertility. https://www.nhs.uk/conditions/infertility/
  6. Practice Committee of the American Society for Reproductive Medicine. Diagnostic evaluation of the infertile female: a committee opinion. Fertil Steril. 2021;116(5):1255-1265.
  7. World Health Organization. Polycystic ovary syndrome. Fact sheet, 22 January 2026. https://www.who.int/news-room/fact-sheets/detail/polycystic-ovary-syndrome
  8. National Institute for Health and Care Excellence. Polycystic ovary syndrome: assessment and management. Draft guideline GID-NG10436, consultation 1 July to 11 August 2026 (final expected December 2026). https://www.nice.org.uk/guidance/gid-ng10436; and NICE news: NICE recommends annual review for PMOS in new draft guideline aimed at improving diagnosis and care. July 2026.
  9. NHS. Irregular periods. https://www.nhs.uk/symptoms/irregular-periods/
  10. Diamanti-Kandarakis E, Dunaif A. Insulin resistance and the polycystic ovary syndrome revisited: an update on mechanisms and implications. Endocr Rev. 2012;33(6):981-1030. doi:10.1210/er.2011-1034
  11. Krassas GE, Poppe K, Glinoer D. Thyroid function and human reproductive health. Endocr Rev. 2010;31(5):702-755. doi:10.1210/er.2009-0041
  12. Melmed S, Casanueva FF, Hoffman AR, et al. Diagnosis and treatment of hyperprolactinemia: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96(2):273-288. doi:10.1210/jc.2010-1692
  13. Gordon CM, Ackerman KE, Berga SL, et al. Functional hypothalamic amenorrhea: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2017;102(5):1413-1439. doi:10.1210/jc.2017-00131
  14. Schliep KC, Mumford SL, Vladutiu CJ, et al. Perceived stress, reproductive hormones, and ovulatory function: a prospective cohort study. Epidemiology. 2015;26(2):177-184. doi:10.1097/EDE.0000000000000238
  15. Joseph DN, Whirledge S. Stress and the HPA axis: balancing homeostasis and fertility. Int J Mol Sci. 2017;18(10):2224. doi:10.3390/ijms18102224
  16. Pasquali R, Pelusi C, Genghini S, Cacciari M, Gambineri A. Obesity and reproductive disorders in women. Hum Reprod Update. 2003;9(4):359-372. doi:10.1093/humupd/dmg024
  17. NHS. When will my periods return after stopping the pill? https://www.nhs.uk/conditions/contraception/when-periods-after-stopping-pill/
  18. NHS. Missed or late periods. https://www.nhs.uk/symptoms/missed-or-late-periods/
  19. National Institute for Health and Care Excellence. Menopause: identifying and assessing, and managing. NICE guideline NG23. https://www.nice.org.uk/guidance/ng23
  20. Gloucestershire Hospitals NHS Foundation Trust Pathology. Progesterone: test information. https://www.gloshospitals.nhs.uk/our-services/services-we-offer/pathology/tests-and-investigations/progesterone/
  21. Teede HJ, Tay CT, Laven JJE, Dokras A, Moran LJ, et al. Recommendations from the 2023 international evidence-based guideline for the assessment and management of polycystic ovary syndrome. Hum Reprod. 2023;38(9):1655-1679. doi:10.1093/humrep/dead156
  22. Royal Berkshire NHS Foundation Trust. Prolactinoma: patient information leaflet. January 2025. https://www.royalberkshire.nhs.uk/media/c3fj2x34/prolactinoma_jan25.pdf
  23. Lim SS, Hutchison SK, Van Ryswyk E, Norman RJ, Teede HJ, Moran LJ. Lifestyle changes in women with polycystic ovary syndrome. Cochrane Database Syst Rev. 2019;3:CD007506.
  24. Harrison CL, Lombard CB, Moran LJ, Teede HJ. Exercise therapy in polycystic ovary syndrome: a systematic review. Hum Reprod Update. 2011;17(2):171-183. doi:10.1093/humupd/dmq045
  25. Marsh KA, Steinbeck KS, Atkinson FS, Petocz P, Brand-Miller JC. Effect of a low glycemic index compared with a conventional healthy diet on polycystic ovary syndrome. Am J Clin Nutr. 2010;92(1):83-92.
  26. Legro RS, Brzyski RG, Diamond MP, et al. Letrozole versus clomiphene for infertility in the polycystic ovary syndrome. N Engl J Med. 2014;371(2):119-129.
  27. Royal Berkshire NHS Foundation Trust. Letrozole: patient information leaflet. https://www.royalberkshire.nhs.uk/media/xytclllq/letrozole.pdf
  28. Gloucestershire Hospitals NHS Foundation Trust. Ovulation induction with oral agents (clomid and letrozole): patient information leaflet. https://www.gloshospitals.nhs.uk/your-visit/patient-information-leaflets/ovulation-induction-with-oral-agents-clomid-and-letrozole
  29. Fitz V, Graca S, Mahalingaiah S, et al. Inositol for polycystic ovary syndrome: a systematic review and meta-analysis to inform the 2023 update of the international evidence-based PCOS guidelines. J Clin Endocrinol Metab. 2024;109(6):1630-1655. doi:10.1210/clinem/dgad762
  30. NHS. Vitamins, supplements and nutrition in pregnancy. https://www.nhs.uk/pregnancy/keeping-well/pregnancy-vitamins-and-supplements/
Leila Martyn

Leila Martyn

Leila is the founder of MyOva, a UK-based hormonal health brand for women with PMOS (PCOS), endometriosis, perimenopause, PMDD and fertility challenges. Drawing on lived experience and scientific research, she shares evidence-based guidance to help women understand their hormones and cycles.

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References