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For Primary Care| Differential diagnosis

Heavy Menstrual Bleeding: What’s the Diagnosis?

Debra Holloway Presents Four Case Studies to Explore the Investigation and Management of Heavy Menstrual Bleeding

Read This Article to Learn More About:
  • the definition and impact of heavy menstrual bleeding (HMB)
  • how investigations differ depending on the signs and symptoms of HMB
  • the management options for HMB of different aetiologies.

Heavy menstrual bleeding (HMB), also known as menorrhagia,1 is defined as menstrual blood loss that interferes with a woman’s physical, social, emotional, and/or material quality of life.2 HMB can present at the menarche and continue throughout a woman’s life to the menopause.3 Although HMB can occur alone,1 it is often associated with symptoms such as dysmenorrhoea, intermenstrual bleeding, and pelvic pain and pressure.2 Left untreated, HMB can lead to complications such as iron deficiency anaemia (see also: Determine the underlying cause of iron deficiency anaemia) or endometrial pathology.4

HMB is very common—one in 20 women aged 30–49 years attend primary care for HMB or menstrual problems, and menstrual disorders account for 12% of all referrals to gynaecology services.2 However, despite the fact that a NICE guideline on HMB has been available for more than 10 years,2 many women with HMB are left undiagnosed and untreated.5 This may be due to a number of factors, including:5

  • lack of awareness among women about the symptoms of HMB and what is considered ‘normal’
  • the stigma surrounding menstrual problems, which may prevent some women from seeking help
  • under-recognition of HMB and its impact on women among healthcare professionals
  • lack of awareness among patients and clinicians of the treatment options and services available for HMB
  • lack of access to diagnostic and therapeutic services for HMB.

The aim of this article is to explore some of the most common conditions that can cause HMB through four case studies, and to give advice on how to investigate and manage HMB in primary care and when to consider a specialist referral.

Causes and Investigations

There are a number of possible underlying causes of HMB (see Box 1).2,6,7 To arrive at the correct diagnosis, careful history taking is needed to ensure that the appropriate investigations are conducted.2

Box 1: Possible Causes of HMB2,6,7
  • No cause (termed dysfunctional uterine bleeding)
  • Extremes of reproductive life
  • Uterine and ovarian pathologies:
    • fibroids
    • endometriosis
    • adenomyosis
    • pelvic inflammatory disease and pelvic infection
    • endometrial polyps
    • endometrial hyperplasia or carcinoma
    • polycystic ovary syndrome
  • Systemic diseases and disorders:
    • coagulation disorders (for example, von Willebrand disease)
    • hypothyroidism
    • obesity
    • diabetes mellitus
    • hyperprolactinaemia
    • liver or renal disease
  • Medications and supplements:
    • chemotherapeutic agents (for example, tamoxifen)
    • anticoagulants
    • copper IUCDs
    • some herbal supplements.

HMB=heavy menstrual bleeding; IUCD=intra-uterine contraceptive device

Figure 1 shows the diagnostic pathways for HMB, which differ depending on symptoms and risk factors.

NICE HMB diagnosis care pathway
Figure 1: HMB—Diagnosis Care Pathway2

1. For example, women with persistent intermenstrual or persistent irregular bleeding and women with infrequent bleeding who are obese or have polycystic ovary syndrome, women taking tamoxifen, women for whom treatment for HMB has been unsuccessful.
2. If high risk for endometrial pathology (see footnote 1).

HMB=heavy menstrual bleeding; TV=transvaginal; TA=transabdominal; MRI=magnetic resonance imaging

© NICE 2021. Heavy menstrual bleeding: assessment and management. NICE Guideline 88. Diagnosis care pathway. NICE, 2021 Available at:

All rights reserved. Subject to Notice of rights. NICE guidance is prepared for the National Health Service in England. All NICE guidance is subject to regular review and may be updated or withdrawn. NICE accepts no responsibility for the use of its content in this product/publication. See  for further details.

In women who present with HMB and whose history suggests a low risk of pathology or abnormality, the NICE guideline states that pharmacological treatment should be considered without further investigation of the cause.2 If treatment is unsuccessful, then referral to specialist care for further investigations should be considered.2 When deciding whether to offer hysteroscopy or ultrasound as the first-line investigation, NICE suggests taking into account the woman’s history and examination.2 Each modality has its advantages and limitations; however, in my experience, a more comprehensive clinical picture will be obtained by performing both investigations, if they are available. More often than not, resources will be the deciding factor, and most units will have easier access to ultrasound than hysteroscopy.

Women at high risk of endometrial pathology, who require referral for investigation in specialist care, are defined in Box 2.

Box 2: Women at Increased Risk of Endometrial Pathology2
  • Women with persistent intermenstrual or persistent irregular bleeding, and women with infrequent heavy bleeding who are obese or have polycystic ovary syndrome
  • Women taking tamoxifen
  • Women for whom treatment for HMB has been unsuccessful.

HMB=heavy menstrual bleeding

© NICE 2021. Heavy menstrual bleeding: assessment and management. NICE Guideline 88. NICE, 2021. Available at:

All rights reserved. Subject to Notice of rights. NICE guidance is prepared for the National Health Service in England. All NICE guidance is subject to regular review and may be updated or withdrawn. NICE accepts no responsibility for the use of its content in this product/publication. See for further details.

Case 1

A 31-year-old woman presents with an ongoing history of HMB. Every month, her periods last for 10 days and consist of 5 days of what she describes as heavy flow. During this time she is unable to leave the house due to the need to change double protection every 45 minutes. Her HMB has got progressively worse over the past few years; she now feels very tired, and dreads her next period. In addition, she is also experiencing some pelvic pain and pressure symptoms (as if the pelvis is heavy), and says that it can sometimes be difficult to pass urine or open her bowels.

A full blood count test, which is recommended by NICE for all women with HMB,2 has shown that she is anaemic. She is up to date with her cervical screening, the results of which were normal. She is not taking hormonal contraception, but uses barrier methods. She has previously had two children via normal vaginal deliveries. Because of her symptoms, she has been referred for an ultrasound scan.2


The most likely diagnosis in this case is fibroids (HMB and pressure symptoms).8 In accordance with the NICE guidance,a pelvic ultrasound scan was ordered, because an endometrial pathology was suspected; this confirmed the presence of fibroids.

HMB is one of the most common symptoms of fibroids,8 which are thought to occur in 20–50% of women older than 30 years.9 The exact prevalence of fibroids is unknown because most women have no symptoms and do not need treatment.8 Fibroids are benign, oestrogen-dependent tumours composed of fibrous and muscular tissue.8 They are relatively common, particularly in women of Afro-Caribbean heritage.8,9 Approximately one-third of women with fibroids experience abnormal uterine bleeding.10 It is believed that fibroids that distort the uterine cavity (submucosal fibroids) are more likely to cause HMB.11 The different types of fibroid are described in Box 3,11 and their position in the uterus is shown in Figure 2.

Box 3: Types of Fibroid and Their Characteristics11
  • Fibroids may develop anywhere within the myometrium. They are described as:
    • subserosal fibroids —when they develop near the outer serosal surface of the uterus and extend into the peritoneal cavity. They are commonly asymptomatic or minimally symptomatic even when relatively large. When they are sufficiently large, they may cause symptoms due to pressure on adjacent structures (such as urinary symptoms due to pressure on the bladder)
    • intramural fibroids —when they develop within the myometrium without extending predominantly into the uterine cavity or peritoneal cavity. They may cause menorrhagia and dysmenorrhea by interfering with the constriction of blood vessels during menstruation
    • submucosal fibroids —when they develop near the inner mucosal surface of the uterus and extend into the uterine cavity. Even relatively small submucosal fibroids may cause significant menorrhagia and dysmenorrhoea or reduce fertility
  • They can be single, or multiple, and their size varies from a few millimetres to 30 cm or larger
  • Subserosal and submucosal fibroids may become pedunculated—attached to the myometrium by a pedicle containing their blood supply.

© NICE 2018. Fibroids: what are fibroids? NICE Clinical Knowledge Summary. Available at:

All rights reserved. Subject to Notice of rights. NICE guidance is prepared for the National Health Service in England. All NICE guidance is subject to regular review and may be updated or withdrawn. NICE accepts no responsibility for the use of its content in this product/publication. See for further details.

Positioning of different types of uterine fibroid
Figure 2: Positioning of different types of uterine fibroid in the uterus

Credit: kanvictory/


In this case, the NICE-recommended management options that would be undertaken in secondary care depend on the size and type of the fibroid.2 NICE recommends considering a levonorgestrel-releasing intrauterine system (LNG-IUS) as the first-line option for women who have fibroids with a diameter of less than 3 cm that are not causing distortion of the uterine cavity (note: this is an off-label use for some LNG-IUSs).2 If this option is declined by the woman or is unsuitable, NICE recommends considering the following pharmacological treatments for fibroids with a diameter of less than 3 cm (note: this is an off-label use for nonsteroidal anti-inflammatory drugs [NSAIDs] and some combined hormonal contraceptives):2

  • nonhormonal:
    • tranexamic acid (an antifibrinolytic)
    • NSAIDs
  • hormonal:
    • combined hormonal contraception (for example, the combined oral contraceptive pill [COCP])
    • cyclical oral progestogens.

For fibroids with a diameter of more than 3 cm, ulipristal acetate can be considered for the intermittent treatment of moderate-to-severe symptoms in premenopausal women, but only when surgical options are not suitable, not successful, or have been declined by the patient, and following discussion of the risks and benefits.2

If pharmacological treatment is unsuccessful or is declined, or symptoms are severe, NICE recommends referral to specialist care for further investigations, alternative pharmacological treatment options, or surgical management.2 Hysteroscopic removal is an option for submucosal fibroids less than 3 cm in diameter.2 For fibroids more than 3 cm in diameter, the surgical options include:2

  • uterine artery embolisation (UAE)
  • myomectomy
  • hysterectomy.

Clinical Outcome

The fibroid was resected under general anaesthetic as a day-case procedure. The next period after this was heavy, but 6 months later, the patient’s periods had settled into a normal pattern of regular bleeding for 5 days. She did not need any other medication or interventions, and after a further 6 months on iron tablets, she was able to stop taking them and did not become anaemic again. If the bleeding had not settled, then an LNG-IUS was suggested as the next step in management; if there had been an increase in pressure symptoms, then myomectomy or UAE would have been the next step.2

Case 2

A 46-year-old woman reports a 3-year history of variation in her menstrual cycle. Her cycle length varies from 21 to 65 days. She bleeds for between 2 and 15 days—the flow can vary as well, but in longer cycles it is much more likely to be heavy. In addition, in longer cycles, she has experienced symptoms such as hot flushes, night sweats, and emotional changes.


In this case, perimenopause is the most likely diagnosis. However, in women with irregular bleeding, NICE recommends hysteroscopy to detect uterine cavity causes of HMB, or pelvic ultrasound if the patient declines hysteroscopy.2 It is also important to ensure that cervical screening is up to date,12 and that the patient does not have an infection. Menopause can be diagnosed on age and symptoms alone, so there is no need for laboratory tests.12 Once the endometrium has been assessed to exclude hyperplasia, a diagnosis of perimenopause can be made.13


To manage HMB in women with no identified pathology, NICE recommends considering an LNG-IUS as the first-line treatment option (note: this is an off-label use for some LNG-IUSs).2 If an LNG-IUS is declined by the woman or is unsuitable, NICE states that clinicians should consider pharmacological treatment. Nonhormonal options include NSAIDs or tranexamic acid;2 the latter can reduce bleeding by 40–50%, but may not improve other problems associated with HMB14 such as painful, long, or irregular periods. Hormonal options include:

  • combined hormonal contraception,2 which can reduce menstrual bleeding and pain and improve cycle regularity; it is necessary to check the eligibility of women aged more than 40 years15
  • cyclical oral progestogens, which can suppress menstruation.

In perimenopausal and menopausal women with HMB, hormone replacement therapy (HRT) is indicated for the management of symptoms of menopause.12 For example, women with HMB and menopausal symptoms can be offered an oestrogen alongside an LNG-IUS (which will provide the progestogen component of the HRT and control the symptoms of HMB). If appropriate, HRT can be provided via the transdermal route rather than orally to reduce the risk of venous thromboembolism.12

If treatment is unsuccessful, patients should be referred to secondary care for further investigations and alternative treatment options.2

Clinical Outcome

Because of the patient’s HMB, symptoms of menopause, and the need for contraception, she opted to have an LNG-IUS inserted, and to start using an oestrogen transdermal gel for menopause symptoms. At a 3-month follow up, the symptoms of menopause had diminished, and her bleeding was lighter but was not following a particular pattern. At 6 months, the bleeding was occasional, and consisted of spotting.

Case 3

A 26-year-old woman presents with a history of HMB. Her cycle is not regular, with gaps of up to 60 days between periods. When she has a period, it can last from 7–15 days, with clots and flooding but no pain. She is also experiencing weight gain and an increase in facial hair.


A diagnosis of polycystic ovary syndrome (PCOS) is most likely in this case. PCOS is the most common endocrine disorder in women of reproductive age16,17—although it is estimated to affect between 2.2% and 26% of these women,18 its true prevalence is unknown.

PCOS is a heterogenous, multifactorial disorder that normally manifests at puberty, and is diagnosed based on the presence of any two of the following three criteria:19

  • oligo- (infrequent) or anovulation, which usually manifests as infrequent or no menstruation
  • signs of hyperandrogenism, such as hirsutism, acne, or elevated levels of total or free testosterone
  • evidence of polycystic ovaries on ultrasound scanning.

The clinical features of PCOS are listed in Box 4.19

Box 4: When to Suspect PCOS19
  • In adults, suspect polycystic ovary syndrome (PCOS) if a woman has one or more clinical features of:
    • infrequent or no ovulation—for example, infertility, oligomenorrhoea, or amenorrhoea
    • hyperandrogenism—for example, hirsutism and acne vulgaris occurring after adolescence
  • In adolescents, suspect PCOS if the girl has:
    • signs and symptoms of hyperandrogenism (such as acne and hirsutism), and
    • irregular menstrual cycles, defined as:
      • normal in the first year post-menarche as part of the pubertal transition
      • more than 1 year to less that 3 years of irregular cycles (more than 45 days or less than 21 days) after the onset of menarche
      • more than 3 years of irregular cycles (more than 35 days or less than 21 days, or less than 8 cycles every year) post-menarche to perimenopause
      • more than 1 year of irregular cycles (more than 90 days for any one cycle) post-menarche
      • primary amenorrhoea by age 15 years or more than 3 years of irregular cycles post-thelarche (breast development)
  • Also suspect PCOS if there is:
    • a family history of PCOS, or
    • indirect evidence of insulin resistance, for example:
      • obesity (especially central obesity)
      • acanthosis nigricans, characterized by dry, rough skin that has grey-brown pigmentation, is palpably thickened, and is covered by a papillomatous elevation (giving it a velvety texture). The condition commonly affects the axillae, perineum, or extensor surfaces of the elbows and knuckles. When the neck is affected, there is often a thin necklace of warty fissures that can spread as a wide band.

© NICE 2021. Polycystic ovary syndrome: when should I suspect polycystic ovary syndrome? NICE Clinical Knowledge Summary. Available at:

All rights reserved. Subject to Notice of rights. NICE guidance is prepared for the National Health Service in England. All NICE guidance is subject to regular review and may be updated or withdrawn. NICE accepts no responsibility for the use of its content in this product/publication. See for further details.

It can be difficult to diagnose PCOS in young women around puberty, so diagnosis should wait until at least 8 years after the menarche.20


A number of investigations are necessary to confirm a diagnosis of PCOS. A blood hormone profile is needed, consisting of total testosterone, sex hormone-binding globulin, free androgen index, follicle-stimulating hormone (FSH), luteinising hormone (LH), prolactin, and thyroid-stimulating hormone.21 Blood test results that show an increased LH to FSH ratio, a significantly elevated total testosterone level, and a slightly raised prolactin level are suggestive of PCOS.21 In addition, adults should undergo ultrasound scanning to confirm polycystic ovaries (note: NICE state that ultrasound should not be used for the diagnosis of PCOS in adolescents), and all patients should undergo a physical examination for signs of virilisation.21 Together, the blood test results, ultrasound scan, and clinical picture can be used to make a diagnosis.16


Women with PCOS may have additional needs over and above those of women with HMB. They may have HMB, especially if their cycles are irregular, and will need a combination of treatments for PCOS and HMB.

Treatment options for HMB in women with PCOS include:2

  • nonhormonal:
    • tranexamic acid
    • NSAIDs
  • hormonal:
    • an LNG-IUS (note: this is an off-label use for some LNG-IUSs)
    • combined hormonal contraception (for example, the COCP)
    • cyclical oral progestogens.

The choice of treatment for PCOS will depend on the patient’s symptoms and fertility needs. If there are long periods of anovulation, the endometrium needs to be protected from the effects of exposure to excess oestrogen unopposed by progestogen, which is a risk factor for the development of endometrial hyperplasia.17 Before treatment, a transvaginal ultrasound scan should be performed to assess endometrial thickness; if this is normal, one of the following treatments to prevent endometrial hyperplasia should be initiated:22

  • a cyclical progestogen for 14 days every 1–3 months
  • a low-dose combined oral contraceptive (such as the COCP, if the patient is eligible23)
  • an LNG-IUS.

If treatment with cyclical hormones or an LNG-IUS is declined by the patient, she should be referred for specialist advice.22

Weight loss can be key to establishing a more regular menstrual cycle.22 If a woman wishes to conceive and is not ovulating regularly, referral to a fertility clinic is indicated.22

Having PCOS has implications for the future, as the condition is related to an increased risk of cardiovascular disease, diabetes, and some cancers, such as endometrial cancer.17,18 NICE recommends that women with PCOS should be encouraged to adopt a healthy lifestyle to reduce the risk of long-term complications.22

Clinical Outcome

The patient started to use tranexamic acid as needed for her HMB, and tried to lose weight to help with her symptoms of PCOS. These measures helped to reduce the amount of bleeding and increase the frequency of cycles. At review, she decided to have an LNG-IUS inserted, as she needed contraception as well.

Case 4

A 39-year-old woman has presented with HMB and painful periods. Her cycle is regular, but the pain is increasing, as is the heaviness of the flow. She has two children. She has come for a review as, for the past 4 months, she has been using tranexamic acid for her HMB as per NICE Guideline (NG) 88,2 and mefenamic acid for her dysmenorrhoea.24 This has helped a bit—her pain score has decreased from 9 to 7—but her symptoms still have a significant impact on her quality of life and functioning.


On examination, the patient had an enlarged, tender uterus. As recommended in the NICE guideline,2 she was referred for a transvaginal ultrasound scan, which confirmed the presence of adenomyosis. Adenomyosis occurs when endometrial tissue grows into the myometrium, and can cause menstrual cramps, lower abdominal pressure, bloating, and heavy periods.7 The exact cause and prevalence of adenomyosis is unknown. The condition is normally diagnosed by transvaginal ultrasound scanning, but if this imaging modality is unsuitable or is declined by the patient, transabdominal ultrasound or magnetic resonance imaging should be considered.2


Given that the patient has already tried nonhormonal pharmacological treatment and further investigations and interventions are required, NICE recommends the following options:2

  • hormonal—an LNG-IUS, combined hormonal contraceptive, or cyclical oral progestogen, all of which are designed to suppress menstruation (note: this is off-label use for some LNG-IUSs and combined hormonal contraceptives)
  • surgical—second-generation endometrial ablation, (the effectiveness of this in women with adenomyosis is unclear), or hysterectomy, the most effective treatment.

UAE has also been proposed as a uterine-sparing option for the treatment of symptomatic adenomyosis after the failure of conservative therapies.25 Although NG88 does not recommend UAE for adenomyosis,2 NICE Interventional Procedures Guidance 473 states that it can be used as an alternative for severe symptoms that do not respond adequately in patients who do not wish to have hysterectomy and/or who wish to preserve their fertility.26

Clinical Outcome

The patient decided to try an LNG-IUS, and was reviewed after this had been in situ for 6 months. The bleeding had decreased and so had the pain, and the patient continued using the LNG-IUS, with the option to review as needed.


The management of HMB can be straightforward if there is no pathology, but is slightly more complex when additional conditions are present that are outside the scope of the NICE guideline. The importance of good history taking and assessment prior to investigations or treatments is demonstrated in these cases, and enables women to have all of their needs met—not only with a reduction of HMB, but also in relation to contraception and help with other symptoms, such as those of menopause and PCOS.

Useful Resources
  • Royal College of Nursing website: Making sense of women’s
  • Royal College of Nursing website: Women’s health pocket
  • Royal College of Nursing website: Promoting menstrual

Debra Holloway

Nurse Consultant, McNair Centre, Guy’s and St Thomas’ NHS Foundation Trust

Note: At the time of publication (March 2022), some of the treatments discussed in this article did not have UK marketing authorisation for the indications discussed. Prescribers should refer to the individual summaries of product characteristics for further information and recommendations regarding the use of pharmacological therapies. For off-licence use of medicines, the prescriber should follow relevant professional guidance, taking full responsibility for the decision. Informed consent should be obtained and documented. See the General Medical Council’s Good practice in prescribing and managing medicines and devices for further information.