Why is my period prolonged and heavy?

Heavy and prolonged menstrual bleeding is a common concern that affects a woman's quality of life. It can start in adolescence or later in life. A woman with heavy and prolonged bleeding may need to change her pad or tampon every hour or two, and her period may last more than 8 days.

What is a normal menstrual period?

When checking whether a period is normal, doctors look at how often it comes (frequency), how long it lasts (duration), how regular it is, how heavy the flow is, and whether there is bleeding between periods.

• 24–38 daysNormal length of the cycle
• 7–9 daysHow much a regular cycle can vary from month to month, depending on age
• Up to 8 daysNormal length of bleeding

The flow should be neither too light nor too heavy. Heavy menstrual bleeding is excessive blood loss that affects a woman's physical or mental wellbeing.

What causes prolonged and heavy menstrual bleeding?

Uterine fibroids

Uterine fibroids are benign tumours that develop within the muscular layer (myometrium) of the uterus. They can sit within the uterine wall (intramural fibroids) or protrude into the uterine cavity (submucosal fibroids). Fibroids are common and mostly affect women above 30 years.

Fibroids stop the myometrium from contracting fully during menstruation, so the blood vessels are not closed off properly. Ulceration or infection of the surface of a submucosal fibroid, and cancerous changes within fibroids, also contribute to irregular and heavy bleeding. Women with fibroids may also have a hormonal imbalance that causes heavy and irregular bleeding.

Anovulation

Anovulation is when the ovary does not release an egg (ovum). Ovulation is controlled by the interplay of several hormones, including estrogen and progesterone, which prepare the endometrium for pregnancy; when pregnancy does not happen, this lining is shed as the period.

With a hormonal imbalance, unopposed estrogen, the lack of a progesterone surge and delayed shedding lead to excessive growth of the endometrium. In conditions that cause anovulation, including polycystic ovarian syndrome (PCOS), hyperprolactinaemia, low body weight and excessive exercise, women may also have irregular cycles with missed months.

Bleeding disorders

Bleeding is normally controlled by contraction of the damaged blood vessels, clumping of platelets, and a fibrin mesh formed over the platelets by the clotting factors. Abnormal blood vessels, low platelets or a lack of clotting factors make it hard to stop bleeding, so a person may have frequent nosebleeds, bruise easily and bleed for a long time from small cuts.

Women with bleeding disorders such as von Willebrand disease may have prolonged and heavy menstrual bleeding.

Endometrial polyps

Endometrial polyps are small, benign growths of the endometrium that protrude into the uterine cavity. They increase the surface area of lining that is shed during menstruation and disrupt normal shedding, leading to heavier and irregular bleeding.

Adenomyosis

Adenomyosis is the presence of endometrial tissue within the myometrium, causing the surrounding muscle to overgrow. It is sometimes called endometriosis interna.

Adenomyosis creates a larger endometrial surface, which results in heavier bleeding. The myometrium contracts during menstruation, and endometrial tissue within it makes those contractions weaker and less effective, so periods become heavier and more painful.

Endometrial hyperplasia and cancer

Endometrial hyperplasia is an overgrowth of normal cells, while cancer involves abnormal, malignant cells. Both mostly develop in women aged 50 to 60 years and are mainly due to unopposed estrogen.

Both can cause prolonged and heavy bleeding by thickening the endometrium and disrupting the normal shedding of the lining.

Medications and intrauterine devices

Medications such as anticoagulants and antiplatelets interfere with clotting and can prolong the period. Some contraceptives, such as progesterone-only methods and non-hormonal (copper) intrauterine devices, are also associated with heavier and prolonged bleeding.

Pelvic inflammatory disease

Pelvic inflammatory disease (PID) is an infection of the pelvic organs, which may include the ovaries, fallopian tubes and uterus. PID, especially endometritis, can cause abnormal bleeding. Endometritis is inflammation of the endometrium and can be caused by infections such as chlamydia.

This article is for general information and does not replace advice from a health worker who knows your situation.

What causes endometriosis?

Endometriosis is a medical condition in which tissue like the lining of the uterus (endometrium) grows outside the uterus. Around 10% of women have it, and it is a common contributor to infertility.

What is endometriosis?

The endometrial tissue may implant on the ovaries, fallopian tubes, pelvic ligaments and lymph nodes, the sigmoid colon and the appendix. Less often, the lungs, kidneys, abdominal scars and even the brain are involved.

Symptoms vary and sometimes depend on the organs involved. Many women have painful periods and chronic pelvic pain, and some develop a pelvic mass.

• About 1 in 10Women affected
• PelvisWhere it is most often found
• InfertilityA common result

What causes endometriosis?

There is no single known cause. These are the main explanations, and more than one may play a part.

Retrograde menstruation

Retrograde menstruation is the backward flow of menstrual blood and tissue through the fallopian tubes into the pelvic cavity. It happens in almost all women, but only causes endometriosis in around 10%, because their immune system cannot clear the blood and tissue efficiently. The cells and tissue that are not cleared implant on the pelvic lining and organs.

Immunological factors

Menstrual blood and tissue in the pelvis trigger the immune system and cause inflammation. The immune cells and the soluble substances they release (cytokines) are meant to clear the foreign tissue, but these cells, particularly macrophages, and the cytokines instead encourage the tissue to grow.

The stimulated macrophages also engulf (phagocytose) sperm, which contributes to infertility. Ongoing inflammation can also lead to scar tissue and pelvic organs sticking together (adhesions).

Blood and lymphatic spread

Endometrial tissue is also believed to travel through the bloodstream to distant sites such as the lungs and the brain. The lymphatic system may also carry the tissue from the uterus to other organs.

Direct implantation

Endometriosis is sometimes found in abdominal and pelvic scars after procedures such as myomectomy, hysterectomy, episiotomy and repair of cervical tears. Endometrial tissue can be dislodged and implanted in a new site, where it grows, forms new blood vessels and feeds from them.

Coelomic metaplasia

Chronic inflammation and irritation of the pelvis from retrograde menstruation may cause other pelvic tissues to transform into endometrial tissue. It is also proposed that Müllerian tissue remnants in the peritoneum could transform into endometrial tissue. Müllerian tissue is a primitive tissue in the developing foetus that eventually forms the fallopian tubes, uterus, cervix and upper part of the vagina.

Hormonal factors

Estrogen is vital to the normal menstrual cycle, and endometriosis is an estrogen-dependent condition: endometriosis tissue responds to estradiol and can produce it locally. During each cycle the misplaced (ectopic) endometrial tissue grows just like the lining of the uterus. The cyclic rise and fall of hormones promotes endometriosis, while continuous hormone suppression with medication reduces it.

Genetics and environment

Genetics seem to play a role: women whose mother, sister or daughter has endometriosis are more likely to develop it. Environmental pollutants may cause mutations in a person's cells or mimic estrogen, which can lead to ovarian or deep infiltrating endometriosis.

This article is for general information and does not replace advice from a health worker who knows your situation.