Introduction

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 

• Menorrhagia (heavy menstrual bleeding)
• Intermenstrual bleeding
• Postcoital bleeding
• Postmenopausal bleeding
• Oligomenorrhoea and amenorrhoea
• Dysfunctional uterine bleeding (see below)
• Irregular menstrual cycle (see below)

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

Presentation

• 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

Investigations

As for heavy menstrual bleeding

Management

• 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
• EMERGENCY TREATMENT
  • 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

References

• 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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