Heavy Menstrual Bleeding

 

In the uterus, estrogen proliferates endometrial cells in the follicular phase of the menstrual cycle, which subsequently thickens the endometrial lining [6],[7]. 

 

When this endometrial lining sheds the thicker it is, the heavier the flow. 

A normal flow is expected to last 4 - 5 days and overall 20 to maximum 80 milliliters of blood to be lost, with the average loss being 60mL. Blood loss that is 80mL or over is classified as a heavy menstrual period, which is estimated to affect up to 20% of women. [8][9] 

 

To estimate blood loss, the following approximates on menstrual blood collection products can be used as a guideline for blood loss. This is typically the average amount of blood they will capture before filling or soaking through, but specifics are dependent on the brand.

 

• Menstrual Cup - 25mL 

• Regular Tampons or Pads - 9mL

• Super Tampons or Pads - 12mL

• Mainstream Regular Period Underwear - 25mL 

 

Cyclical Breast Tenderness

 

Breast enlargement and sensitivity can correlate to elevated estrogen, but is particularly noticeable in conjunction with progesterone deficiency. This is because estrogen stimulates ductal elongation, branching and epithelial proliferation, processes that increase the volume and density of the breast. In parallel, estrogen promotes vascular permeability and interstitial fluid retention within the connective stroma, contributing to sensations of fullness, swelling, and tenderness. This experience is most notable when estrogen is at its highest, and particularly if progesterone is low and unable to oppose the effects of estrogen on the breast. [10][11]

 

Depending on the hormone profile this becomes most noticeable:

 

• 2 days before ovulation - roughly day 10 after after day 1 of bleeding

• Symptoms alleviated during ovulation 

• Returns 6 - 7 days before the next menstrual cycle, and can persist until menstruation - particularly in cases of low progesterone.

 

Menstrual blood clotting

 

Estrogen shifts the balance of the bodies clotting system toward a prothrombotic state by increasing the levels of clotting proteins such as factors II, VII, VIII, X, and fibrinogen, while reducing natural anticoagulants like antithrombin and protein S. Furthermore Estrogen also raises ‘von Willebrand factor’, which makes platelets stickier and enhances clot formation 

 

This means the elevated estrogen levels are more likely to clot the blood, especially when pooled in the uterus before exiting the body. This manifests as the passage of visible clots during menstruation. While these clots are not dangerous, they reflect estrogen both thickening the uterine lining and promoting clotting activity, which leads to a heavier, and sometimes more clot-filled menstrual bleed. [45][46]

 

Increased Risk of Endometriosis

 

Endometriosis clinically manifests as:

 

• Menstrual cramps that are much worse than average

• Pelvic pain often persists outside of menstruation

• Pain during intercourse, especially when lesions affect uterosacral ligaments 

• Bowel symptoms that worsen during menstruation including - pain, diarrhoea, constipation or bleeding

A key problem in endometriosis is the imbalance in estrogen receptors. Normally, ERα (estrogen receptor alpha) controls most estrogen activity in a healthy endometrium, but in endometriosis, ERβ (estrogen receptor beta) is overexpressed by about 34 times the normal level. This shift causes excess tissue growth and invasion, as ERβ drives genes like RERG and SGK1 that help cells proliferate and migrate.
 

Because ERβ activation depends on the presence of estradiol, strategies that reduce the overall estrogen load, whether through liver clearance or aromatase inhibition can decrease ERβ activity. This reduction dampens the inflammatory cycle, slows lesion growth, and alleviates symptoms. [41]

 

Thrush / Candida Overgrowth

 

High estrogen levels can also affect your body’s response to pathogens, such as Candida albicans. In one study, three C. albicans strains were tested in the presence of estradiol. All 3 strains showed increased growth and survival rates and improved drug resistance [13].

 

Uterine Fibroids

 

• Heavy menstrual bleeding

• Pelvic pain and pressure 

• Urinary frequency or urgency from bladder pressure

• Constipation from bowel compression, and low back pain.
   

Uterine fibroids are hormonally responsive non-cancerous tumors, and their growth is strongly driven by estrogen. Fibroid tissue has been shown to overexpress estrogen receptors (primarily ERα) compared with normal uterine muscle, making it especially sensitive to circulating estradiol. Estrogen promotes cell proliferation, extracellular matrix production, and vascular changes within the fibroid, all of which allow the tumor to grow and persist. [14][15]

 

Breast, Thigh and Hip Weight

 

Excess estrogen induces an overexpression of estrogen receptors such as ERα and ERβ [16].

These receptors are concentrated in tissues within the breast, hip and thigh region. They serve several functions, but play a large involvement in fat deposits and have been found in increased numbers to subsequently increase the size and number of adipocytes (fat cells), within those regions. [17][18]

 

Studies experimenting with increases in estrogen have been found to induce fatty deposits particularly to those regions. Noting that menopausal declines in estrogen have been shown to cause fat redistribution more to the abdominal region [19].  

 

Melasma - Skin Pigmentation

 

Estrogen plays a central role in the development of melasma because it directly stimulates the skin’s melanocytes, the cells responsible for producing pigment. In laboratory studies, 17β-estradiol, the body’s main estrogen, was shown to increase the proliferation of melanocytes and to slightly enhance tyrosinase activity, the key enzyme that drives melanin production. Therefore, when estrogen levels are high, melanocytes become more active and produce more pigment, which appears as the darker patches of skin typical of melasma. [42][43]