Reviewed June 2019

5 things your heavy periods during menopause could mean

Young woman hands holding hygienic tampon

Heavy menstrual bleeding is a common problem for women of all ages. However, during the perimenopause, a time when women tend to presume their periods will start becoming lighter, they can actually become heavier. During a period, losing between 25-80mls of blood is considered to be normal. Losing more than 80mls of blood during one cycle, that is, soaking a pad or tampon every two hours or less, and/or your period lasting more than seven days, is defined as heavy bleeding or menorrhagia.

Heavy menstrual bleeding is the most common complaint during the perimenopause, occurring in up to 30% of women.1 While heavy periods during perimenopause can be entirely normal, the causes of heavy periods can be due to problems with the ovaries and/or uterus (localised), or due to problems with other parts of the body that can affect your cycles or affect bleeding (systemic).

Here, we’ve looked at five common causes of heavy periods during perimenopause to help you understand what could be happening to your body. If you are experiencing heavy periods, however, it is important to go to your doctor and get checked out to ensure it is nothing serious.

Is my heavy bleeding just a normal part of menopause?

The most common cause of heavy periods during menopause is hormonal imbalance. During the beginning of a normal menstrual cycle, a hormone called follicle stimulating hormone (FSH) rises which stimulates follicles (eggs) to mature in the ovaries. Many follicles are stimulated during a cycle and these follicles produce oestrogen which is required to thicken the lining of the womb (endometrium). Only one follicle will be mature enough to be ovulated.

As there is a decline in the number of follicles at perimenopause, the body tries to recruit as many as possible at the beginning of the cycle. It does this by increasing FSH levels. This part of the cycle can take longer than usual as it becomes harder to recruit eggs. There is an increase in oestrogen from the many follicles stimulated. These higher levels of oestrogen act on the endometrium during the long stimulation period, making it thicker and resulting in heavy periods.2

Ovulation is required for a period to occur. The progesterone produced by the ovulated egg, and its subsequent withdrawal, is what causes a period. During the perimenopause, anovulation (no ovulation) becomes more frequent. Thus there is still oestrogen production by the follicles causing the endometrium to thicken, but no progesterone. The endometrium only continues to thicken. Eventually the lining outgrows its blood supply and breaks down, resulting in shedding which women see as irregular and/or prolonged and/or heavy bleeding.

Could I have a polyp?

Polyps are soft outgrowths which can arise from the uterus and can cause heavy periods. They are usually benign with prevalence between 6% and 32%.3 Different research shows different prevalences and as polyps don’t cause any symptoms apart from bleeding they are often under diagnosed. The prevalence usually increases with age which is why women may complain of heavy periods/irregular bleeding during the time of their menopause.4 It is still not known why polyps cause menorrhagia. A different blood supply to the polyp (different to the surrounding endometrium) and impeded blood drainage may contribute to heavy bleeding.5

Polyps can be detected on ultrasound and removed using hysteroscopy (when a camera is inserted into the womb via the vagina to locate the polyp, and then forceps are used to pull it out — patients are sedated or under anaesthesia for this). Very rarely can a polyp be cancerous (0.8-3%).6 This risk increases with age, with post-menopausal women being most at risk, but there is no way of checking if polyps are cancerous until they are removed and sent to the lab.

Do I have fibroids?

Fibroids are benign growths that arise from the muscle of the uterus. The majority of women with uterine fibroids are asymptomatic and so are often undiagnosed. Their incidence increases with age, and they are more common in Afro-Caribbean women.7 Prevalence ranges between 5% and 21% and can rise to 70-80% by the age of 50.8 Their growth is stimulated by oestrogen and progesterone.

Fibroids just under the endometrium and those that protrude into the cavity of the womb can cause menorrhagia via a combination of factors. Firstly, the increase in oestrogen during the perimenopause can cause fibroids to enlarge, increasing the surface area of the endometrium which in turn exposes more endometrium to oestrogen. Secondly the growth of fibroids can impede blood flow into and from the womb which can cause congestion. Thirdly, fibroids can inhibit the contraction of the uterine muscle and its vessels, which is an effective way of stemming bleeding.9

As fibroids are hormone dependent, they regress after the menopause. Small fibroids that protrude into the uterine cavity can be removed by hysteroscopy.

Could it be hypothyroidism?

Menstrual abnormalities, particularly menorrhagia, can be one of the first noticeable symptoms of thyroid abnormalities, particularly hypothyroidism.10 The incidence increases with age and thyroid dysfunction can be masked by menopausal symptoms.

The physiology behind menorrhagia in hypothyroidism is anovulation (which, as mentioned earlier, can cause heavy bleeding) due to thyroid hormone deficiency. Correct levels of thyroid hormone levels are required to produce luteinising hormone (LH) which is needed to trigger ovulation. If the balance is disturbed, there can be a delay in LH production. Hypothyroidism can also alter coagulation factors which are required for blood to clot effectively, and therefore this can result in excessive bleeding.11

Could it be a coagulation problem?

Although most women with a coagulation (blood clotting) problem are likely to have had menorrhagia at a young age and therefore be diagnosed, it is possible for clotting problems to occur later in life. Bleeding disorders can occur during perimenopause and women that do have sudden heavy bleeding should be investigated.12 Medication such as warfarin, heparin, or steroids can also effect your clotting, as can disorders of the liver, thyroid, bone marrow.

Besides the causes stated above, there are many other causes of heavy periods that occur in younger women that still apply to menopausal women such as pregnancy (miscarriage) and infection. If you are having periods, it is possible to become pregnant no matter your age.

Heavy periods are becoming more common due to the rise in body mass index of the general population. Adipose tissue (fat tissue) produces oestrogen which has the same effect on your endometrium as the oestrogen from follicles. If heavy bleeding is new to you, you should see your doctor. Endometrium exposed to prolonged periods of oestrogen can result in a condition called endometrial hyperplasia which can be a precursor to cancer. However, the risk of developing endometrial cancer with simple hyperplasia is low – less than 5% over 20 years.13

There are medications available to treat heavy periods depending on the cause. Medications to reduce bleeding such as tranexamic acid can be prescribed by your doctor. Your GP may decide to start you on a progesterone-only contraception if the bleeding is due to hormonal imbalance. The Mirena coil is very effective as a form of progesterone and can be used in women with fibroids. In addition, it can prevent endometrial hyperplasia. Women who have thyroid dysfunction may find that their periods improve once their thyroid levels return to normal.

Anaemia can occur with heavy bleeding. If you notice increased fatigue, dizziness or breathlessness please see your doctor to check your haemoglobin levels. There is no set amount of blood you need to lose to qualify for iron supplements. If you have been experiencing heavy bleeding, there is no harm in commencing oral iron tablets.

Your heavy periods may be nothing or it could be an indicator that something else may be going on inside your body. We as doctors would be very happy to see you as we want to be able to rule out anything serious.

Last updated June 2019
Next update due 2021

Dr Shreya Patel, MBBS MSc BSc DFSRH

Shreya is a London-based doctor specialising in Obstetrics and Gynaecology. Her passion in global and public health, family planning, and reproductive rights led her to pursue a masters in Public Health at Harvard. She is a strong believer that women should have easily accessible, accurate information about their health, to enable them to make decisions about their health that are right for them.

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  1. Lotha, L., & Borah, A.,  ‘Clinicopathological evaluation of abnormal uterine bleeding in perimenopausal women’, International Journal of Reproduction, Contraception, Obstetrics and Gynecology, vol 5, no. 9, 2016, pp. 3072-3074.
  2. Prior, J., ‘Perimenopause: The complex endocrinology of the menopause transition’, Endocr Rev, vol. 19, no. 4, 1998, pp. 397-428.
  3. Dreisler, E., et al., ‘Prevalence of endometrial polyps and abnormal uterine bleeding in a Danish population aged 20–74 years’, Ultrasound Obstet Gynecol, vol. 33, no.1, 2008, pp. 102-108.
  4. Ibid.
  5. Salim, S., et al., ‘Diagnosis and management of endometrial polyps: A critical review of the literature’, Journal of Minimally Invasive Gynaecology, vol. 18, no. 5, 2011, pp. 569-81.
  6. Savelli, L., et al., ‘Histopathologic features and risk factors for benignity, hyperplasia and cancer in endometrial polyps’, American Journal of Obstetrics and Gynecology, vol. 188, no. 4, 2003, pp. 927-931.
  7. Zimmermann , A., et al., ‘Prevalence, symptoms and management of uterine fibroids: an international internet-based survey of 21,746’, BMC Women’s Health, vol. 12, no. 6, 2012.
  8. Ibid.
  9. Simms-Stewart, D.,  and Fletcher, H., ‘Counselling patients with uterine fibroids: A review of management and complications’, Obstetrics and Gynecology International, vol. 2012, 2012.
  10. Gowri, M., et al., ‘Role of thyroid function tests in women with abnormal uterine bleeding’, International Journal of Reproduction, Contraception, Obstetrics and Gynecology, vol. 3, no. 1, 2014, pp. 54-57.
  11. Byna, P., et al., ‘Thyroid abnormality in perimenopausal women with abnormal uterine bleeding’, International Journal of Research in Medical Sciences, vol. 3, no. 11, 2015, pp. 3250-3253.
  12. Philipp, C.S., et al., ‘Age and the prevalence of bleeding disorders in women with menorrhagia’, Obstetrics and Gynecology, Vol 105, no. 1, 2005, pp. 61-66.
  13. RCOG, ‘Management of Endometrial Hyperplasia’, Green-top Guideline, no. 67, 2016, [available online],, (accessed 25 June 2019).

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