Postmenopausal bleeding (PMB) is a red flag symptom that should never be considered normal. While most cases are due to benign causes, approximately 10% of women with PMB will be diagnosed with endometrial cancer. As such, early recognition, prompt investigation, and appropriate referral are key to optimising outcomes.
Definition and common causes
PMB is defined as any vaginal bleeding occurring 12 months or more after the final menstrual period. It is a common presentation in general practice and accounts for approximately 5% of gynaecological consultations among postmenopausal women.
Common causes include:
- Endometrial atrophy (most common benign cause)
- Endometrial polyps
- Hormone replacement therapy (HRT), especially during the first 6 months
- Endometrial hyperplasia
- Endometrial or cervical malignancy
Even if the bleeding is light or a single episode, it should not be dismissed.
Initial GP workup
The recommended first-line investigation is a transvaginal ultrasound (TVUS).
Endometrial thickness <=4 mm in women with PMB is generally considered reassuring and associated with a low risk of malignancy (approx 1%). However, further assessment is indicated if any of the following are present:
- Persistent or recurrent bleeding
- The endometrium appears heterogeneous or irregular
- Endometrial thickness >4 mm
- A focal lesion or polyp is identified
Ensure that cervical screening is up to date to exclude cervical pathology.
When to refer to a gynaecologist
Referral to a gynaecologist is recommended if:
- TVUS shows thickened endometrium (>4mm),heterogeneity, or intrauterine abnormalities ultrasound findings.
- The woman is not on HRT and presents with unexplained PMBThe patient has risk factors such as:
- obesity
- type 2 diabetes
- unopposed oestrogen exposure
- family history of endometrial cancer or colorectal cancer (consider Lynch syndrome)
In secondary care, we routinely perform hysteroscopy and endometrial sampling for definitive assessment of abnormal findings.
HRT-related bleeding: What’s normal?
Sequential HRT may cause regular withdrawal bleeding; this is expected. Continuous combined HRT should ideally induce amenorrhoea within 4-6 months
Investigate bleeding if it occurs:
- Beyond 6 months of starting HRT
- After achieving amenorrhoea, and bleeding resumed
- Heavily or persistently, even while on therapy
Take-home points
- Always investigate postmenopausal bleeding, it’s not normal at any stage
- A transvaginal ultrasound is the first step
- Refer promptly if the endometrial thickness is >4 mm, or if bleeding is recurrent,or if ultrasound is abnormal.
- Early diagnosis of malignancy significantly improves survival rates.
References
- Clark TJ, Stevenson H. Endometrial pathology in the postmenopausal woman. Best Pract Res Clin Obstet Gynaecol. 2021;74:23–37. doi:10.1016/j.bpobgyn.2021.01.002
- Munro MG, et al. Abnormal uterine bleeding in the postmenopausal years: the role of transvaginal ultrasonography. Am J Obstet Gynecol. 2017;217(1):80–87. doi:10.1016/j.ajog.2017.01.002
- Archer DF, et al. Bleeding patterns of a continuous combined regimen of low-dose estradiol and norethindrone acetate in postmenopausal women. Menopause. 2020;27(3):290–296. doi:10.1097/GME.0000000000001445
- Fung MF, et al. Management of postmenopausal bleeding. J Obstet Gynaecol Can. 2018;40(9):e722–e733. doi:10.1016/j.jogc.2018.05.006
- American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 149: Endometrial cancer. Obstet Gynecol. 2015;125(4):1006–1026. doi:10.1097/01.AOG.0000462976.61250.90
- Van den Bosch T, et al. Terms, definitions and measurements to describe sonographic features of the endometrium and intrauterine lesions: consensus statement from the International Endometrial Tumor Analysis (IETA) group. Ultrasound Obstet Gynecol. 2019;53(5):609–618. doi:10.1002/uog.20134
