Explanation
Origin
The exact cause of fibroids remains unknown. The initial trigger that causes abnormal and excessive growth of the uterine muscle cells has not been identified. None of the proposed factors fulfils the criteria required to be considered a proven cause of disease. For example:
- Consistent findings:
In diseases like malaria, multiple studies consistently identify the same cause-the plasmodium parasite. With fibroids, however, different studies report different possible causes. - Temporality:
For a factor to be considered a cause, the effect must occur after exposure. For malaria, a person must have plasmodium parasites before falling sick. In fibroids, no single factor is consistently found in all affected individuals. - Biological gradient:
Greater exposure should lead to more severe disease. In malaria, having more parasites leads to more severe illness. In fibroids, no known factor becomes more harmful with increased exposure.
Because of these gaps, the exact cause of fibroids remains uncertain. What exists instead are hypotheses, some of which are complex. The most prominent include:
- Chromosomal abnormalities:
About 40 per cent of fibroid cases show some form of chromosomal abnormality. Chromosome 6, which helps regulate immunity, inflammation, and cellular function, is often implicated. Alterations such as deletions or rearrangements may disrupt normal uterine muscle cell behaviour, leading to uncontrolled growth. - Role of polypeptide growth factors:
These are protein-based molecules that regulate cell growth, differentiation, and survival. They act as messengers, binding to specific receptors on cells and triggering pathways that modify gene expression.
Examples include epidermal growth factor, insulin-like growth factor, and transforming growth factor. These may stimulate fibroid growth directly or through the influence of oestrogen. - Family history:
Many women with fibroids report a positive family history, suggesting a possible genetic predisposition.
