Abnormal Uterine Bleeding
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Abnormal uterine bleeding is a common presenting problem in general practice

  • Accounts for about 4% of presentations to general practice
  • 20% of women complain of heavy period bleeding – however about 50% of these have a normal amount of blood loss when investigated – perception is not reliable
  • Heavy menstrual bleeding is the most common cause of iron deficiency in the developed world
  • Don’t forget about possible pregnancy and its complications when presented with a patient with abnormal uterine bleeding!
  • Non-menstrual bleeding (postcoital, intermenstrual and postmenopausal) always warrant further investigation and consider early referral to gynaecology

In this article we discuss a brief overview of abnormal uterine bleeding. Individual types of abnormal uterine bleeding are discussed separately.

Types of abnormal uterine bleeding 

The normal cycle

  • 30-40mls average blood loss per cycle
  • <80mls is considered “normal”
  • >80mls is considered menorrhagia / heavy menstrual bleeding (HMB)
  • The two most common causes of HMB are fibroids and adenomyosis
  • Many drugs can alter menstrual bleeding, including steroids, anticoagulants and cannabis
  • Keeping a menstrual diary can be a good way to estimate blood loss – there are now lots of apps that can help to record this data

Defining normal

  • Menarche usually occurs between the ages of 10-16 (mean age 13)
    • Periods can be irregular for up to three years after menarche
    • Irregular periods after this time is considered abnormal
  • Normal range of cycle – 21-35 days
    • Mean 26-28 days
  • Menstrual flow – 2-7 days
    • Mean 3-4 days
  • Normal blood loss 20-80ml
    • Mean 30-40mls
  • Estimating volume – any flow such that menstrual pads are not able to absorb the flow is considered abnormal
  • Normal endometrial thickness – 6-12mm
  • Anovulatory cycle – defined as serum progesterone >20nmol/L in the mid-luteal phase (5-10 days before menses)
  • Abnormal uterine bleeding is more common at the extremes of reproductive age. Cancer is a more likely cause in women at the upper end of the range, and is less than 1 in 100 000 in women under 35

Dysfunctional Uterine Bleeding (DUB)

  • Defined as excessive uterine bleeding for which no organic cause can be identified.
  • Diagnosis of exclusion
  • Common – 10-20% of women will suffer it at some stage
  • Usually ovulatory rather than anovulatory
  • Common in late 30s and early 40s
  • Up to 40% of patients initially diagnosed as DUB will ultimately have fibroids, endometrial polyps or some other organic cause later identified


  • Heavy bleeding, saturated pads, “accidents”, “flooding” clots
  • Prolonged bleeding
    • Menstruation >7 days, OR
    • Heavy bleeding > 4 days
  • Frequent bleeding – more often than every 21 days
  • Usually do not have pelvic pain or tenderness


As for heavy menstrual bleeding


  • Menstrual calendar
  • Ensure no iron deficiency anaemia
  • Reassurance about the absence of identified pathology
  • Consider drug therapy
    • First line are antiprostaglandins – NSAIDs and tranexamic or mefanamic acid. Start as soon as bleeding starts and continue for 5 days. Between 60-80% of patients can control symptoms with one of these agents alone
    • Contraceptive pill is second line – about 80% of patients will respond to COC
    • Hormonal IUD (Mirena) is the most effective hormonal agent – reduces bleeding by 95%
    • Progesterone reduced bleeding by 85% – although pill preparations usually much less effective. Depo-provera will induce amenorrhoea in about 50% of patients within 1 year
    • COC reduces bleeding by 50%
    • Tranexamic acid reduces bleeding by 40%
    • NSAIDs reduce bleeding by 30%
  • In extreme cases – consider surgical management if medical management is unsuccessful and fertility is no longer desirable
    • Endometrial ablations
    • Hysterectomy
    • Tranexamic acid 1-1.5g PO TDS until bleeding stops


Irregular menstrual cycle

  • Usually hormonal in origin
  • Only rarely is there an organic cause in patients under 35
    • Consider PCOS – particularly if there are any other features present
  • COC or POP often used to treat symptomatically
  • Patients over 35 need thorough investigation for an organic cause – usually endometrial biopsy +/- hysteroscopy


  • Murtagh’s General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
  • Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.

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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) FRACGP currently works as a GP and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University, and is studying for a Masters of Sports Medicine at the University of Queensland. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

This Post Has 2 Comments

  1. ed

    in management you have put IUD , do you mean IUC? mirena
    IUD- copper can make bleeding even heavier

  2. Dr Tom Leach

    The terminology can be a bit confusing and is not always standardised. IUD (Intrauterine device) can refer to both the mirena IUD or the copper IUD. Generally these days most people have a mirena IUD, and the copper IUD now seems to be quite rare (certainly in my experience). In this instance I meant to refer to mirena (I have made this more clear). I have also updated the almostadoctor article on the IUD to try to clear up some of this confusing terminology. ( https://almostadoctor.co.uk/encyclopedia/coils-iud-and-ius )

    Some people use IUD to generally mean mirena, and typically specific “copper” when this appropriate.

    You might also see some other terms. As far as I can tell IUC (intrauterine contraception) and IUCD (intrauterine contraceptive device) can refer to either the copper or the mirena variant.
    I have also seen IUS (intrauterine system) used to refer to the mirena variant only (and not the copper coil)

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