Culdocentesis is a procedure that checks for abnormal fluid in the space just behind the vagina. This area is called the cul-de-sac.

First, you will have a pelvic examination. Then, the health care provider will grasp the cervix with an instrument and lift it slightly.

A long, thin needle is inserted through the wall of the vagina (just below the uterus). A sample is taken of any fluid found in the space. The needle is pulled out.

You may be asked to walk or sit for a short time before the test is done.

You may have an uncomfortable, cramping feeling. You will feel a brief, sharp pain as the needle is inserted.

This procedure is rarely done today because a transvaginal ultrasound can show fluid behind the vagina.

It may be done when:

• You have pain in the lower abdomen and pelvis, and other tests suggest there is fluid in the area
• You may have a ruptured ectopic pregnancy or ovarian cyst

No fluid in the cul-de-sac, or a very small amount of clear fluid, is normal.

Fluid may still be present, even if not seen with this test. You may need other tests.

A sample of fluid may be taken and tested for infection.

If blood is seen in the area, you may need emergency surgery.

Risks include puncturing the uterine or bowel wall.

You may need someone to take you home if you were given a sedative.

Braen GR, Pierce DL. Culdocentesis. In: Roberts JR, Hedges JR, eds. Clinical Procedures in Emergency Medicine. 5th ed. Philadelphia, Pa: Saunders Elsevier; 2009:chap 57.