The endometrium is the layer lining the inside of the uterus, which thickens and is shed during the menstrual cycle. Endometrial biopsy is performed to investigate whether there is abnormal thickening (hyperplasia), a precancerous change or cancer in this layer. The procedure is usually done in the examination room without anesthesia and takes a few minutes.
When is it performed?
- Bleeding after menopause
- Abnormal uterine bleeding: particularly in people over 45, or in younger people with long-term exposure to estrogen not balanced by progesterone (for example, obesity or polycystic ovary syndrome) or whose bleeding continues despite treatment
- A thickened uterine lining seen on ultrasound
- Bleeding while taking medicines that affect the uterine lining, such as tamoxifen
- Changes in glandular cells (AGC) found on a Pap smear (depending on age and risk factors)
In people with bleeding after menopause, the first assessment is often a transvaginal ultrasound. If the lining is thin, a biopsy may not be needed; if it is thick or the bleeding continues, a tissue sample is taken.
How is it done?
Before the procedure, the possibility of pregnancy is ruled out, with a pregnancy test if needed. Blood-thinning medicines should be reported beforehand. On the examination table, a speculum is placed in the vagina and the cervix is cleaned with an antiseptic solution; if needed, a local anesthetic is applied to the cervix and the cervix is held steady with an instrument. A thin, flexible plastic cannula resembling a drinking straw (Pipelle) is then passed through the cervix into the uterus. The plunger inside the cannula is drawn back to create gentle suction, and a small tissue sample is taken from the lining of the uterus. The sample is sent for pathological examination.
The procedure is not performed, or is postponed, in pregnancy or when there is an active pelvic infection or an acute infection of the cervix or vagina. If the cervical canal is narrow, it may not be possible to obtain a sample.
Pain and after the procedure
Period-like cramping is felt while the sample is taken. The cramping is usually brief but may be more severe in some people. Dizziness or a feeling of faintness may occur during or after the procedure. Afterwards, light spotting and cramping may last a few days; using pads rather than tampons is advised during this time. Simple painkillers can be used if needed.
Limitations of the result
With this method, a sample is taken from only part of the uterine lining. For this reason, changes confined to a small area, such as a polyp, may be missed. Particularly after menopause, the tissue obtained may not be sufficient for examination. If bleeding continues or recurs despite a normal result, further assessment is carried out.
Alternative methods
- Hysteroscopy: viewing the inside of the uterus with a thin camera passed through the cervix. It allows a biopsy to be taken under direct vision from a suspicious area; changes such as polyps can be removed during the same procedure. Depending on its extent, it is performed in the examination room or under anesthesia.
- Curettage (D&C): dilation of the cervix and removal of tissue from inside the uterus, performed under anesthesia. When done for diagnosis, it may be combined with hysteroscopy.
These methods are considered when a sample cannot be obtained in the examination room, when the tissue obtained is insufficient or when the result does not match the complaints.
Possible risks
Cramping and light spotting for a few days are the most common side effects. Possible risks include dizziness or a feeling of faintness, prolonged bleeding and infection. Perforation of the uterus or a tear of the cervix is rare. If the sample is insufficient, the procedure may need to be repeated or another method used.