Thickened lining of the womb (Thickened endometrium)
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What is thickened endometrium?

Thickened endometrium is a condition where lining of the womb is abnormally thickened, even after having an ultrasound scan immediately after the menstrual cycle.

In a normal menstruating woman, if she undergoes ultrasound scan, immediately after her menstrual cycle, the lining of the womb is very thin. On the contrary, if on ultrasound, immediately after the menstrual cycle, if the lining womb is thick (where the expectation is that it should be thin), then, this needs further evaluation.

Usually, scenario being women having a scan randomly and once identified to be thick, then the best way to sort this out is to repeat the ultrasound scan in the few days following last day of  menstrual cycle.

Causes of  thickened endometrium

But one should be aware that, there are pathological causes of abnormally thickened lining of the womb. This kind of scenario is seen in women who have irregular periods such as women with PCOS, women who have weight issues such as obesity or morbid obesity, or women who took tamoxifen following treatment for breast cancer, or certain types of medical preparations in the IVF setting.

If the thickened endometrial issue is persistent and has other risk factors such as PCOS, obesity or women who are on HRT and is experiencing abnormal bleeding, then, they may benefit from further advanced investigative modality such as hysteroscopy and lining of the womb biopsy. This investigation can be done either with local anaesthesia or under general anaesthesia.

Sometimes thickened endometrium on ultrasound could represent a polyp, which is a localised overgrowth of lining of the womb.

Endometrial hyperplasia is a condition in which the endometrium (lining of the uterus) is abnormally thick.

There are four types of endometrial hyperplasia. These vary by the amount of abnormal cells and the presence of cell changes. The types are:

  • Simple
  • Complex
  • Simple atypical
  • Complex atypical

Identifying Abnormal Endometrial Symptoms

The primary symptom of abnormally thickened endometrium is abnormal bleeding. This could be in the form of prolongation of the bleeding phase, heavy menstrual bleeding or intermenstrual bleeding or unscheduled unpredictable bleeding. The other menstrual patterns are,

  • Menstrual bleeding that is heavier or longer-lasting than usual
  • Menstrual cycles (amount of time between periods) that are shorter than 21 days
  • Intermenstrual bleeding between periods (IMB)
  • Missing periods for a long time ( PCOS)
  • Post-menopausal bleeding (PMB)

What causes abnormally thickened endometrium?

The common reason for abnormally thickened endometrium being hormonal imbalance.

Endometrial hyperplasia is caused by too much oestrogen and/or not enough progesterone. Both hormones play a role in the menstrual cycle. Oestrogen makes the cells grow, while progesterone signals the shedding of the cells. A hormonal imbalance can produce too many cells or sometime abnormal cells ( hyperplasia)


Abnormally thickened endometrium could manifest with abnormal uterine bleeding which can be a symptom for many things or sometimes missing periods.

A pelvic ultrasound measures the thickness of endometrium and assesses regularity of womb cavity. It also gives an opportunity to assess whether the thickened lining is all over the womb cavity ( global) or just in few areas ( focal)

The pathological cause of thickened endometrium is endometrial hyperplasia ( reversible precancerous condition) or rarely cancer of the lining of the womb

When in doubt or concerned about the given situation, the usual recommendation is to have a look (hysteroscopy) and biopsy of the lining of the womb ( hysteroscopy and biopsy).

Because of technological advances, a hysteroscope used can be as tiny as a ballpoint pen refill (<2mm). Hysteroscopy gives an opportunity to visualise the womb cavity and obtain the visual impression, obtain still picture or a video, so that, these can be reviewed at a later stage such as in the multidisciplinary meeting

Can anyone prevent Abnormally thick endometrium?

  • Correct use of HRT preparations, if menopausal and is on HRT
  • Optimisation of PCOS
  • Optimisation of body weight (normalisation of BMI)
  • Review of tamoxifen or letrozole if on it
  • To take birth control pills or to have artificially induced menstrual cycles, if periods are missing over 6 months in <50 years and not pregnant.

Treatment of thickened endometrium

Treatment options for thickened endometrium depends on the cause.

Scenario 1 : If a wrongly timed scan in a healthy woman, a repeat scan by an expert sonographer in the postmenstrual period is all that is needed

Scenario 2 : Thickened endometrium in the postmenstrual phase, review of situation and explore whether the patient needs hysteroscopy and biopsy. If the patient has significant risk factors, such as obesity, suffers from PCOS or family history of uterine or ovarian cancer or has had multiple IVF cycles or has taken tamoxifen or letrozole,  situations like this will need further tests of reassurance such hysteroscopy and biopsy

Scenario 3 : Postmenopausal and is experiencing abnormal bleeding and has thickened endometrial lining and  will probably benefit from hysteroscopy and biopsy

Living with thickened endometrium

In most cases, thickened endometrium is because of a functional disorder and is amenable to treat, if the cause is correctly identified. There will be a range of options, starting from, regulating menstrual cycles, to regular withdrawal bleeds, to use of Levonorgestrel intrauterine system in select group of women where fertility is not desired.

If body weight is a contributing factor, then a long-term strategy to optimise body weight will certainly help.

Endometrial hyperplasia is very treatable. Patients may have to with their doctor to create a treatment plan. If they have a severe type or if the condition  (complex hyperplasia or complex atypical hyperplasia, such patients need regular monitoring such as ultrasound and surveillance hysteroscopy and biopsies

Mahantesh Karoshi
Mahantesh Karoshi

I'm a Consultant Obstetrician & Gynaecologist and Women's Health Expert. I believe in educating my patients to contribute to achieving the best possible clinical and holistic outcomes. By taking this approach, I enable and empower my patients whilst addressing their issues and concerns. I run a private practice with an extremely high standard of professionalism. My patients are directly involved in their care and management in all stages. My approach to my patient's problems is built on dedication and passion, drawing on analytical thinking and my on-time honored reading, teaching medical professionals nationally and internationally.