Causes of Heavy Periods
The causes of heavy periods are diverse and can range from temporary hormonal fluctuations to more serious underlying medical conditions. Understanding the causes of heavy periods is essential not only for effective treatment but also for identifying whether the symptom is a sign of something more complex. While some individuals experience heavy menstrual bleeding without any clear reason. Referred to as dysfunctional uterine bleeding—others may have structural, hormonal, or systemic issues that require medical intervention.
One of the most common causes is hormonal imbalance, particularly involving oestrogen and progesterone. These two hormones regulate the menstrual cycle by controlling the buildup and shedding of the uterine lining. When they are not in balance—such as during puberty or perimenopause. The lining may become excessively thick, leading to heavier bleeding during menstruation. Polycystic ovary syndrome (PCOS), thyroid dysfunction. Furthermore, insulin resistance are conditions that can contribute to hormonal imbalance and result in erratic or heavy periods.
Uterine fibroids are another leading cause. These non-cancerous growths develop within the muscular wall of the uterus and can vary in size from a few millimetres to several centimetres. Depending on their size and location, fibroids can distort the uterine cavity and increase the surface area of the endometrium. Leading to heavier, more prolonged periods. Women with fibroids often report pelvic pressure, urinary frequency, and pain in addition to menorrhagia.
Causes of Heavy Periods
Endometriosis is a chronic condition in which tissue similar to the uterine lining grows outside the uterus. Most commonly on the ovaries, fallopian tubes, or pelvic lining. While the condition is more famously associated with pelvic pain and infertility, it can also lead to heavy menstrual bleeding. The misplaced endometrial-like tissue bleeds in response to the menstrual cycle. However, because it has no way to exit the body, it can cause internal inflammation and further disrupt normal menstruation.
Another significant cause is adenomyosis, a condition where endometrial tissue grows into the muscular wall of the uterus. This condition thickens the uterus and leads to both heavy periods and intense cramping. Adenomyosis is most commonly diagnosed in women aged 35 to 50 and can coexist with other uterine abnormalities such as fibroids or endometriosis.
Polyps—small, soft growths on the lining of the uterus or cervix—can also cause excessive bleeding. These may be benign or, in rare cases, precancerous. Polyps tend to be more common in people nearing menopause, and while some remain asymptomatic, others contribute to heavy or irregular periods and spotting between menstrual cycles.
In some cases, the causes of heavy periods stem from bleeding disorders, such as von Willebrand disease or platelet function disorders. These inherited conditions affect the blood’s ability to clot properly, making menstrual bleeding heavier and more prolonged. In fact, studies have shown that a notable percentage of adolescent girls who seek treatment for menorrhagia have an undiagnosed bleeding disorder. Screening for these conditions is important, particularly when there is a family history or symptoms like frequent nosebleeds, easy bruising, or prolonged bleeding after minor injuries.
Certain medications can contribute as well. Anticoagulants like warfarin, aspirin, or newer blood thinners interfere with normal clotting and may exacerbate menstrual bleeding. Similarly, long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) can irritate the stomach and increase bleeding tendencies in some individuals. Hormone replacement therapy (HRT), often used during perimenopause, may also alter the menstrual cycle and lead to heavier bleeding in certain cases.
Causes of Heavy Periods
Intrauterine devices (IUDs), particularly copper IUDs, are known to increase menstrual flow in some women. While they are a highly effective form of birth control, they can make periods heavier and more painful, especially during the first few months after insertion. Hormonal IUDs, on the other hand, usually reduce bleeding, making them a potential treatment rather than a cause.
Pelvic inflammatory disease (PID)—a bacterial infection of the reproductive organs—can also lead to heavier periods. It typically occurs as a result of untreated sexually transmitted infections like chlamydia or gonorrhoea. Alongside abnormal bleeding, PID often causes pelvic pain, fever, and an abnormal vaginal discharge. If left untreated, PID can cause scarring, infertility, or chronic pain.
In rare cases, endometrial or cervical cancer may cause abnormal or heavy menstrual bleeding. While cancer is not the most common cause, doctors must always rule it out. This is especially true for women over 40 or younger women who have ongoing or unusual bleeding. Also, bleeding after menopause is a serious warning sign and needs quick evaluation.
Stress, significant weight changes, and lifestyle factors such as excessive exercise or poor diet can also temporarily disrupt the menstrual cycle, leading to irregular or heavy bleeding. Chronic stress affects the hypothalamic-pituitary-ovarian axis, the central regulatory system for menstruation, which can result in erratic hormone production and menstrual disturbances.
In adolescents, the causes are often physiological and temporary. During the first few years after menarche (the onset of menstruation), cycles are often anovulatory (without ovulation), which means progesterone isn’t produced to counterbalance oestrogen. This hormonal imbalance causes the uterine lining to build up excessively and then shed irregularly and heavily.
Causes of Heavy Periods
In summary, the causes of heavy periods include a wide array of hormonal, structural, systemic, and lifestyle-related factors. Some causes, such as fibroids or endometriosis, require targeted medical or surgical treatment, while others—like hormonal imbalances—may resolve with lifestyle changes or medication. Because heavy periods can affect overall health and quality of life, identifying the specific cause is a crucial first step toward effective treatment and long-term menstrual health.
