Abnormal Uterine Bleeding

Dr Tom Leach

6 years ago

Contents

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.

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

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

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
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

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.