Irregular periods are one of the most common health concerns women bring to their doctors. Most of the time, they are caused by harmless hormonal fluctuations, stress, thyroid issues, or PCOS. But in some cases, abnormal uterine bleeding can be an early warning sign of a gynecologic cancer — particularly uterine (endometrial) cancer.
Knowing the difference between irregular but benign and irregular and concerning could save your life.
What Counts as Irregular Bleeding?
Normal menstrual cycles vary from 21 to 35 days, with bleeding lasting 2 to 7 days. You should pay attention if you experience:
- Periods that are significantly heavier or longer than usual
- Spotting or bleeding between periods
- Bleeding after sexual intercourse
- Periods occurring more frequently than every 21 days
- Any vaginal bleeding after menopause
- Bleeding during pregnancy
Common Non-Cancerous Causes of Irregular Bleeding
Most irregular bleeding has a benign cause:
- Hormonal imbalance — the most common cause in women of reproductive age
- Polycystic Ovary Syndrome (PCOS)
- Thyroid disorders — both hypothyroidism and hyperthyroidism
- Uterine fibroids — benign muscle tumours of the uterus
- Uterine polyps — benign growths of the uterine lining
- Perimenopause — the years leading up to menopause
- Certain medications — including blood thinners and some contraceptives
- Extreme weight changes or exercise
When Irregular Bleeding Could Be Cancer
The bleeding pattern most strongly associated with gynecologic cancer is:
Postmenopausal Bleeding
Any vaginal bleeding after menopause — even a single episode of light spotting — should be investigated immediately. Approximately 10% of postmenopausal women with vaginal bleeding have endometrial (uterine) cancer. This is the most important red flag.
Persistently Heavy or Prolonged Periods
Periods that are consistently much heavier than before, or that last longer than 7 days, particularly in women over 40, warrant evaluation to rule out uterine cancer or pre-cancerous changes.
Bleeding Between Periods in Women Over 40
While intermenstrual bleeding (bleeding between periods) is common and often benign, in women approaching perimenopause or menopause, it should be investigated.
Bleeding After Intercourse
Post-coital bleeding (bleeding after sex) is a classic early symptom of cervical cancer. While it can also be caused by cervical erosion or infection, it should always be evaluated.
What Investigations Does a Doctor Order?
Depending on your age, symptoms, and history, your doctor may recommend:
- Transvaginal ultrasound — to assess the thickness of the uterine lining and examine the ovaries
- Endometrial biopsy — a sample of the uterine lining to check for cancer or pre-cancer
- Pap smear and HPV test — to screen for cervical abnormalities
- Hysteroscopy — a small camera inserted into the uterus for direct visualisation
- Blood tests — including thyroid function, CA-125, and complete blood count
The Bottom Line
Irregular periods are common — but they should never simply be accepted without investigation, especially if they are new, worsening, or occur after menopause. The earlier an abnormality is found, the more treatment options you have and the better your outcome will be.
If you are experiencing abnormal bleeding of any kind, please do not delay seeking medical advice.
Dr. Monisha Gupta is a Gynecologic Oncologist at Fortis Hospital, Shalimar Bagh, New Delhi, specialising in gynecologic cancers including uterine, ovarian, cervical and vulvar cancer.
