Quick answer. Abnormal vaginal bleeding is most often caused by hormonal (anovulatory) cycles, fibroids, polyps, infection, or contraception, but the single biggest red flag is any bleeding after menopause, which must be promptly assessed to exclude endometrial (womb) cancer.
Abnormal vaginal bleeding means any bleeding that differs from your normal menstrual pattern: periods that are unusually heavy or prolonged, bleeding between periods, bleeding after sex, or any bleeding after you have gone through menopause. In Singapore it is one of the most common reasons women visit a polyclinic or gynaecologist, and most causes are benign and treatable.
That said, abnormal bleeding can occasionally be the first sign of something serious, so it should never simply be ignored. Resources such as HealthHub and SingHealth encourage women not to delay assessment, especially when bleeding is heavy, persistent, occurs after sex, happens during pregnancy, or appears after menopause. This guide explains the common causes and helps you judge when to seek care urgently.
At a glance
| Bleeding pattern | Possible causes | Suggested action |
|---|---|---|
| Heavy or prolonged periods | Fibroids, hormonal imbalance, polyps, clotting issues | See a doctor; ask about iron levels |
| Bleeding between periods | Polyps, hormonal/anovulatory cycles, contraception, infection | Arrange a gynaecology review |
| Bleeding after sex | Cervical polyp, cervicitis, infection, cervical changes | See a doctor to examine the cervix |
| Any bleeding after menopause | Atrophy, polyps, and importantly endometrial cancer | Prompt assessment, do not delay |
| Bleeding during pregnancy | Miscarriage, ectopic, placental problems | Urgent medical attention |
Red flags: when to seek help urgently
Most abnormal bleeding is not an emergency, but some situations need prompt or immediate care:
- Any bleeding after menopause (no period for 12 months or more) must be assessed promptly to exclude endometrial cancer, even if it is just a single episode of spotting.
- Bleeding during pregnancy or if you could be pregnant is urgent, as it may signal miscarriage or an ectopic pregnancy.
- Very heavy bleeding with dizziness, feeling faint, a racing heart, or breathlessness can indicate dangerous blood loss. Call 995 or go to the nearest A and E.
- Bleeding after sex, or persistent bleeding between periods, should be checked by a doctor even if it is light.
When in doubt, it is always safer to be reviewed.
Hormonal and anovulatory bleeding
Irregular or unpredictable bleeding is frequently due to hormonal cycles where ovulation does not occur regularly (anovulation). This is common in teenagers in the first few years after periods start, in women approaching menopause (perimenopause), and in conditions such as thyroid disorders or polycystic ovary syndrome (PCOS).
Without regular ovulation, the womb lining can build up and shed erratically, causing heavy, light, frequent, or skipped bleeding. Treatment often involves hormonal regulation, but assessment is needed to confirm the cause.
Fibroids and polyps
Fibroids are non-cancerous growths of the muscular wall of the womb and are very common. They can cause heavy or prolonged periods, pelvic pressure, and sometimes anaemia from blood loss. Polyps are small soft growths on the lining of the womb or cervix that can cause bleeding between periods or after sex.
Both are usually benign and can be diagnosed with an ultrasound scan and, where needed, a hysteroscopy. Many cases are managed with medication, while others may benefit from a minor procedure to remove the growth.
Infection, contraception, and other causes
Pelvic and vaginal infections, including sexually transmitted infections, can inflame the cervix and cause bleeding between periods or after sex, sometimes with discharge or pelvic pain. These are diagnosed with swabs and treated with antibiotics.
Hormonal contraception is another common reason for irregular bleeding. Spotting is especially frequent in the first few months of starting the pill, an implant, an injection, or a hormonal intrauterine device. This usually settles, but persistent or heavy bleeding should be reviewed so other causes are not missed.
Postmenopausal bleeding: the key red flag
Menopause is confirmed when you have had no period for 12 consecutive months. Any vaginal bleeding after this point is considered abnormal and should be assessed promptly. While the most common cause is thinning and dryness of the vaginal and womb lining (atrophy), or a benign polyp, postmenopausal bleeding is also the classic warning sign of endometrial (womb) cancer.
The good news is that when endometrial cancer is caught early, treatment is often very effective, which is exactly why prompt assessment matters. Investigation usually involves a pelvic ultrasound to measure the womb lining and, if needed, a sample of the lining (endometrial biopsy). Do not wait to see if it happens again.
Which specialist should you see?
For most abnormal vaginal bleeding, the right specialist is an obstetrician and gynaecologist (O and G), who can examine you, arrange an ultrasound, and perform any further tests such as a hysteroscopy or endometrial biopsy. You can start with a GP or polyclinic, but persistent, heavy, post-sex, or any postmenopausal bleeding warrants specialist review.
See our directory of the best gynaecologists in Singapore to find a doctor for assessment. If you ever feel faint from heavy blood loss, or have bleeding in pregnancy, treat it as an emergency and call 995.
What to expect at the appointment
It helps your doctor a great deal if you can describe your bleeding pattern: how heavy it is, how long it lasts, whether it occurs between periods, after sex, or after menopause, and how your normal cycle usually looks. Keeping a simple diary, or using a period-tracking app, gives a clear picture. The doctor may examine you, take swabs if infection is possible, and arrange a pelvic ultrasound to look at the womb and ovaries. Where the womb lining needs closer assessment, a hysteroscopy or a small sample of the lining (endometrial biopsy) may be recommended. Bring a list of your medicines, including any contraception or hormone treatment.
Looking after yourself with heavy bleeding
Heavy or prolonged bleeding can lower your iron levels over time, leaving you tired, breathless or pale. Eating iron-rich foods and discussing whether you need an iron supplement or a blood test can help. Track how many pads or tampons you are using, as this helps your doctor judge how heavy the bleeding really is. Seek urgent care if you feel faint, dizzy or have a racing heart, which can signal significant blood loss.
Common questions
Is bleeding after menopause always serious?
Most causes are benign, such as thinning of the lining, but any bleeding after menopause must be checked promptly because it can occasionally be the first sign of womb cancer, which is very treatable when found early.
Can stress cause irregular bleeding?
Stress and other factors can affect your cycle through hormonal changes, but persistent irregular bleeding still deserves assessment so other causes are not missed.
Is spotting on contraception normal?
Spotting is common in the first few months of starting hormonal contraception and usually settles. Persistent or heavy bleeding should be reviewed.
Related guides
- Best Gynaecology Clinics in Singapore — our editorial shortlist
- gynaecology clinics directory
- Find a gynaecologist
- Find an endocrinologist
- Find a urologist
Sources
- NHS: Vaginal bleeding
- NHS: Heavy periods
- HealthHub Singapore
- Mayo Clinic: Endometrial cancer
- SingHealth
Part of our Women’s health & gynaecology guides · Browse all health topics