What is endometrial hyperplasia?
The endometrium is the lining that builds up in the uterus each month and then sheds, as a period, if a pregnancy does not occur. Endometrial hyperplasia is when the lining develops abnormally and becomes too thick. Depending on how abnormal (“atypical”) the cells appear when studied under a microscope, this determines the risk of progression to uterine cancer (ranging from ~3% to ~30%). It can occur if you menstruate, or even after menopause.
What causes endometrial hyperplasia?
Endometrial hyperplasia occurs when there is an imbalance of hormones: either too much oestrogen or a combination of high oestrogen and low levels of progesterone. Conditions that cause this imbalance include: being overweight or obese; polycystic ovarian syndrome; irregular periods (with long gaps between periods); oestrogen-only hormone replacement therapy (without progesterone); and tamoxifen. The risk is also increased in people who have diabetes, those who have never been pregnant and if you have a genetic condition known as Lynch syndrome.
Who does endometrial hyperplasia affect?
Endometrial hyperplasia can occur at any age once menstruation has commenced, but is more commonly seen in people who are post-menopausal.
What symptoms may I get?
The most common presentation is abnormal uterine bleeding. For people menstruating, this could be a change in their periods: usually heavier and lasting longer, or bleeding in between periods. If you are post-menopausal, any bleeding is abnormal and should be investigated.
How is endometrial hyperplasia investigated?
The first step in investigating abnormal uterine bleeding is to have a pelvic ultrasound. A transvaginal ultrasound (where a probe is placed inside the vagina), is the most accurate way to assess the lining of the uterus compared to an abdominal ultrasound. There is lack of agreement as to the exact thickness cut-off, but it is generally accepted that if you are post-menopausal, the lining of the uterus should be ≤ 4mm. If you are still menstruating, the thickness varies depending on where in your cycle you are. The lining can be up to 16mm thick if it is just prior to your period. The ultrasound looks at not only the thickness but also what the lining looks like and if there are any suspicious features for hyperplasia.
If you have a thickened endometrium and abnormal uterine bleeding, it is recommended that you have a biopsy of the endometrium. One option is to have a look inside the uterus with a camera (‘hysteroscopy’) and take a sample of the lining of the uterus (‘curette’). Another option is to have an endometrial sample taken in the rooms (a ‘Pipelle’). A pipelle sample has detection rates > 91% but if this was to show hyperplasia, you would be recommended to have a hysteroscopy and curette to ensure full sampling of the lining and that there is no underlying cancer.
How is endometrial hyperplasia treated?
Hyperplasia is a precursor to endometrial cancer, and requires treatment. The gold standard treatment for endometrial hyperplasia is a hysterectomy (removal of the uterus). If you are post-menopausal, the advice is to have your uterus, cervix, fallopian tubes and ovaries removed.
If you desire a pregnancy, fertility sparing options include progesterone treatment – this is through the Mirena intrauterine device or oral tablets. A Mirena IUD has been shown to give much higher rates of regression to normal endometrium, compared to treatment with oral progesterone. Using a progesterone-containing IUD (Mirena) also limits the absorption of progesterone throughout the body which limits the side-effects you get from taking a progesterone tablet, such as increase appetite, mood changes and nausea.
If you are being managed with progesterone (either IUD or oral tablets), the lining of the uterus will be biopsied every 6 months to assess for regression (reversal) or progression of your endometrial hyperplasia. Your endometrium needs to return to normal and have three consecutive normal samples prior to trying for pregnancy.
Frequently asked questions
If I have abnormal bleeding from the vagina does that mean I have endometrial hyperplasia?
Not necessarily. There are other reasons you can have abnormal bleeding such as polyps, fibroids, infections (including sexually transmitted infections, STIs), abnormal cells on the cervix, atrophy (low oestrogen) in the vagina and stress. The periods also tend to become heavier as you approach menopause and don’t ovulate every cycle. It is important to see your doctor to have a pelvic ultrasound, cervical screening test and STI screen to exclude other causes of abnormal bleeding.
If I have post-menopausal bleeding (PMB), what are the chances I have endometrial hyperplasia?
The majority of scientific studies have investigated rates of endometrial cancer rather than endometrial hyperplasia specifically. If you have PMB, your risk of endometrial cancer is ~10%.
Should I see a gynaecologist if I have an abnormal bleeding and a thickened endometrium?
Yes. If the other possible causes (above) have been excluded, it is important to get a biopsy of the endometrium to exclude hyperplasia.