An endometrial biopsy involves testing a sample of the endometrial lining of the uterus. This test is done to check the hormone levels and endometrial lining are consistent with the timing of the menstrual cycle. In other words, is the lining what would be expected on that day of your cycle?
The endometrial biopsy involves the physician inserting a catheter through the cervix and into the uterus. A sample of the endometrial tissue is extracted. This tissue is sent to a lab for testing. The test only takes a few minutes.
Most women experience mild to moderate discomfort with this test. The pain is sometimes compared to strong period cramp. Once the test is over, the pain subsides quickly. A pain reliever such as ibuprofen can be taken for the pain, if needed.
This test is done in the latter half of the cycle. The hormone levels need to be tested after ovulation in order to detect problems such as a luteal phase defect. Women may worry about a pregnancy occurring during the cycle in which the biopsy is taken. The risk of miscarriage is less than one percent, so there is little risk.
When the results of the test vary from the menstrual cycle by two days or more, the cycle is said to be out of phase. If the results show the endometrial lining is out of sync with the menstrual cycle, the test may be repeated. The test is not super sensitive and may not be completely accurate. In addition, hormone levels may vary from one cycle to the next.
Since levels can vary from month to month, the doctor will probably order a second biopsy to confirm the findings. Similar results on the second test will show if a pattern exists. If the test results are the same during the following cycle, the doctor will then make a decision regarding the course of treatment.