Endometrial hyperplasia
What is endometrial hyperplasia?
Endometrial hyperplasia is broadly defined as an excessive cellular proliferation leading to an increased volume of endometrial tissue. It is characterised by an increase in the endometrial gland-to-stroma ratio greater than 1:1.
Endometrial hyperplasia is further classified as simple or complex, with or without atypia. This classification system is based on the complexity and crowding of the glandular architecture.
Menorrhagia- Intermenstrual bleeding
- Postmenopausal bleeding
- Unscheduled bleeding on hormone replacement therapy
However, endometrial hyperplasia can also be asymptomatic and can spontaneously regress without being detected.
Histological classification of endometrial hyperplasia
Aetiology and risk factors
Oestrogen stimulates endometrial proliferation.A relative excess of oestrogen (exogenous or endogenous) compared with progesterone is considered to be one of the principle causes in endometrial hyperplasias.
- Unopposed oestrogen,
- Obesity, particularly in nulliparous women,
- Diabetes,
- Hypertension
- Polycystic ovary syndrome,
Incidence and diagnosis
Efficacy and safety profile
The efficacy of Mirena® in preventing oestrogen-induced hyperplasia in peri-menopausal and postmenopausal women has been assessed in various studies.
No hyperplasia was detected in any of the trials, regardless of dose, method of administration of oestrogen component or duration of therapy.
Mirena® significantly decreased menstrual bleeding compared with conventional oral hormone replacement therapy (P=0.001, N=200).
Continuing Mirena® use during the transition from contraception to ERT has no known additional adverse events on the vaginal bleeding profile.
The proportion of patients who had difficulties in coping with any items from the Women's Health Questionnaire decreased over time, during both the contraception and ERT phases with Mirena®.
PP-PF-WHC-IUS-GB-0108 | March 2025