Intermenstrual Bleeding: When Should You Be Concerned?

Discovering blood on your underwear a week or two after your last period can be concerning. While an isolated light episode may be harmless, persistent and/or heavy intermenstrual bleeding could be a sign of an underlying medical condition. This includes hormonal imbalance, infection, or, in rare cases, cancer.

This article aims to help you differentiate harmless spotting from more worrisome conditions and to prepare you for what to expect when you consult a gynaecologist.

What Is Intermenstrual Bleeding?

Intermenstrual bleeding is vaginal bleeding that occurs outside your usual menstrual cycle. It can present as a faint pinkish vaginal discharge or brownish stain and can mimic a light period.

Intermenstrual bleeding can occur at any stage in a woman’s reproductive cycle. 

This includes:

• The early years after menstruation begins, when hormone levels are still adjusting 

• The perimenopause phase, when ovulation becomes erratic

• When taking hormonal medication or 

• After a gynaecological procedure.

Common Causes of Intermenstrual Bleeding

Intermenstrual bleeding can be due to:

• Hormonal fluctuations: The hormones oestrogen and progesterone regulate the menstrual cycle and the womb’s lining. An imbalance in either hormone can cause intermenstrual bleeding. 

• Birth-control breakthrough bleeding: This occurs when starting on a new birth control method or missing one or more birth control pills. This will usually resolve spontaneously within the first few menstrual cycles.

• Ovulation: This usually occurs during the middle of a menstrual cycle and resolves spontaneously within 48 hours. 

• Polycystic ovary syndrome (PCOS): Patients with PCOS have irregular ovulation, which can lead to erratic, sometimes intermenstrual bleeding.

• After an abortion: A medically induced termination can leave healing tissue prone to bleeding for weeks. Retained products of conception can also lead to infection and intermenstrual bleeding. 

• Uterine fibroids or polyps: These growths can cause prolonged, frequent and/or heavy intermenstrual bleeding.

• Cervical inflammation or damage: Vaginal or cervical infections can cause inflammation and intermenstrual bleeding.

• Sexually transmitted infections (STIs): Chlamydia and gonorrhoea can cause inflammation of the cervix (cervicitis), leading to post-coital or intermenstrual bleeding. These infections may be silent, with 50-70% of chlamydia patients not noticing any symptoms.

Conditions Associated with Intermenstrual Bleeding

These are some of the conditions that are associated with intermenstrual bleeding.

• Endometriosis: This can cause tissue outside the womb to bleed with each period, resulting in vaginal spotting that can be mistaken for intermenstrual bleeding.

• Thyroid disorders: An underactive thyroid (hypothyroidism) can cause heavy and/or prolonged periods and can resemble intermenstrual bleeding.

• Pregnancy-related causes: Implantation bleeding can mimic intermenstrual bleeding. This is usually mild and resolves spontaneously. Ectopic pregnancy and miscarriages can also cause similar signs.

• Cervical or endometrial cancer: High-risk human papillomavirus (HPV) related cervical lesions and early endometrial cancer often present as intermenstrual bleeding.

Endometrial Cancer: A Critical Differential Diagnosis

Endometrial cancer is the fourth most common cancer diagnosed in females in Singapore. One of the key signs for endometrial cancer is intermenstrual bleeding. 

The following are risk factors for endometrial cancer:

• Obesity (BMI greater than 30kg/m2)

• Chronic anovulation (e.g. PCOS)

• Diabetes

• Early menarche or late menopause

• Use of medications such as tamoxifen

• Family history of endometrial or colon cancer

Key symptoms include:

• Intermenstrual or postmenopausal bleeding

• Heavy or prolonged periods

• Bleeding after intercourse

A pelvic ultrasound is used to assess endometrial thickness as part of your evaluation. If the lining is abnormally thick, a hysteroscopy and dilation & curettage (D&C) or endometrial biopsy may be recommended to rule out endometrial cancer. Early detection and treatment are crucial. The American Cancer Society reports that the 5-year survival rate for endometrial cancer is as high as 95%.

Consulting A Gynaecologist - What to Expect

History Taking

Your gynaecologist will take a comprehensive medical history by asking specific questions to identify potential risk factors or causes for your intermenstrual bleeding.

Speculum and vaginal examination

Your gynaecologist will perform a vagina examination to assess the vagina and cervix for potential causes for your symptoms. He will also assess for the presence of any abnormal vaginal discharge and will send off specimens if required.

Investigations

You may be asked to undergo the following tests:

• Hormonal and thyroid blood tests: This is to determine if your symptoms may be caused by hormonal disturbances.

• Pap smear and HPV testing: This is to determine if cervical changes (pre-cancer or cancer) are responsible for your symptoms. 

• Vaginitis panel: This is to screen for yeast, bacteria and parasitic infections.

• STI panel: This is to screen for chlamydia or gonorrhea.

• Pelvic ultrasound scan: This is to look for fibroids, polyps, ovarian cysts or a thickened endometrium that could account for intermenstrual bleeding. 

If your ultrasound shows an intrauterine growth (fibroid or polyp) or if your uterine lining is thickened, your gynaecologist may recommend a hysteroscopy and dilation & curettage (D&C).

Get treatment for menstrual disorders

Abnormal bleeding, such as intermenstrual bleeding, can affect your quality of life. More importantly, it can be a sign of a serious medical condition. If you have intermenstrual bleeding, see a gynaecologist to get it checked at the earliest opportunity. Dr Daniel Koh is a specialist obstetrician and gynaecologist with more than 15 years of experience in managing intermenstrual bleeding. 

Book an appointment with him today