Endometrial biopsy is frequently used to evaluate abnormal uterine bleeding. It is a relatively quick and cost-effective way to sample the endometrium to allow for direct histological evaluation of the endometrium. It is essential to have as endometrial cancer is the fourth most common cancer among women. The American Cancer Society estimates that there will be 61880 new uterine cancer cases and 12,160 related deaths in 2019.[rx] The patient does not need to undergo more invasive procedures as endometrial biopsies have a high sensitivity and specificity for detecting endometrial hyperplasia and endometrial malignancy that is equal to the diagnostic accuracy dilatation and curettage (D&C) procedure.[rx]
Anatomy and Physiology
Uterus corpus: the body of the uterus that is located in a female’s lower abdomen, between the bladder and the rectum.
- Endometrium – the lining of the uterine cavity. It is a layer of glandular epithelium and stroma that changes thickness during the cycle.
- Cervix – the cervix is the most inferior part of the uterus. The cervical canal connects the uterus to the vagina.
- Vagina – a passageway that connects the cervix and the vulva (the external genitalia).
Indications of Endometrial Biopsy
Abnormal uterine bleeding
Evaluation for endometrial neoplasia or precancerous hyperplasia
Surveillance of previously diagnosed endometrial hyperplasia or cancer
Evaluation of uterine response to hormone therapy
Contraindications of Endometrial Biopsy
Acute pelvic inflammatory disease
Acute cervical infection
Acute vaginal infection
Clotting disorder or coagulopathy
Biopsy container with formalin
Sterile and non-sterile gloves
Topical benzocaine gel (20%) or benzocaine spray
Endometrial suction catheter (pipelle) x2
A clinician in the outpatient setting can perform this procedure independently. However, it may be prudent to have an assistant to help in preparation and specimen handling.
Minimal preparation is required for this procedure. The procedure should be discussed with the patient in detail to include the procedure’s risks and benefits. Informed consent must be obtained before starting the procedure.
Any women of reproductive age or with the potential for pregnancy should have a documented negative pregnancy test prior to the procedure.
The patient can take an NSAID 30 to 60 minutes before the procedure to reduce the pain associated with cramping.
Prophylactic antibiotics are not necessary during endometrial sampling for the prevention of surgical site infection or bacterial endocarditis.[rx]
The first part of the procedure is non-sterile. The patient is first placed in the lithotomy position, and a bimanual examination is done to determine the uterine size and position of the uterus. The speculum can now be inserted to allow for cervical visualization. Of note, if a Pap smear is necessary, this is an ideal time to obtain the appropriate samples before continuing the procedure. Once visualized, the cervix can be anesthetized and cleansed by spraying a 20 percent benzocaine spray for 5 seconds then applying an iodine solution. At this time, it is appropriate to wash hands and don sterile gloves.
The next step is to determine the depth of the uterus, which is done with a uterine sound. The first step is to stabilize the cervix. A tenaculum is placed on the anterior lip of the cervix and allows the provider to straighten the uterocervical angle. The uterine sound is then inserted to an average depth of 6 to 10 cm within the uterus. The provider can discern that the sound is fully inserted when feeling resistance from the fundus. One common complication at this step is that the uterine sound will not pass through the internal cervical os; this can be overcome by using cervical dilators. The smallest size is inserted, followed by successively larger dilators’ insertion until the sound can reach the fundus.
Once achieving adequate os dilation and determining the uterus’ depth, the sampling pipeline can be inserted. The pipeline should be advanced until encountering resistance. This resistance should be at the same depth as the sounding of the uterus. Once the pipeline is in the uterine cavity, the internal piston on the catheter is fully withdrawn, creating suction at the catheter tip. This suction, accompanied by moving the tip with an in and out motion, allows for sample collection. This motion should be completed with a 360-degree twisting motion to reach all four quadrants of the endometrium. The pipeline is now removed, and the collected tissue sample is placed into a formalin solution. A second pass into the uterus can be done to ensure the collection of adequate tissue. If a second pass is made, ensure the catheter is not contaminated when being emptied of the first specimen.
Gently remove the tenaculum to complete the procedure. Most bleeding will be controllable with pressure via cotton swabs or a sponge stick. If bleeding persists, use silver nitrate sticks to cauterize the site.
The most common side effect of an endometrial biopsy is cramping. This can be significantly reduced with the administration of pre-procedure NSAIDs. Once the procedure is completed, women may report light vaginal bleeding or spotting for several days. Less common side effects include uterine perforation, pelvic infection, and bacteremia. They are monitored for by instructing the patient with strict return precautions to include returning to the office for fever, cramping continuing for more than 48 hours, increasing pain, bleeding heavier than a normal menstrual period, or any foul-smelling discharge.
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