Culdocentesis is a procedure that checks for abnormal fluid in the space just behind the vagina. This area is called the cul-de-sac.
How the Test is Performed
First, you will have a pelvic exam. Then, the health care provider will hold 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.
How to Prepare for the Test
You may be asked to walk or sit for a short time before the test is done.
How the Test will Feel
You may have an uncomfortable, cramping feeling. You will feel a brief, sharp pain as the needle is inserted.
Why the Test is Performed
This procedure is rarely done today because a transvaginal ultrasound can show fluid behind the uterus.
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.
- Blunt abdominal trauma.
No fluid in the cul-de-sac, or a very small amount of clear fluid, is normal.
What Abnormal Results Mean
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 found in the fluid sample, 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 medicines to relax.
Braen GR, Kiel J. Gynecologic procedures. In: Roberts JR, Custalow CB, Thomsen TW, eds. Roberts and Hedges' Clinical Procedures in Emergency Medicine and Acute Care. 7th ed. Philadelphia, PA: Elsevier; 2019:chap 57.
Eisinger SH. Culdocentesis. In: Fowler GC, ed. Pfenninger and Fowler's Procedures for Primary Care. 4th ed. Philadelphia, PA: Elsevier; 2020:chap 161.
Hur HC, Lobo RA. Ectopic pregnancy: etiology, pathology, diagnosis, management, fertility prognosis. In: Gershenson DM, Lentz GM, Valea FA, Lobo RA, eds. Comprehensive Gynecology. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 17.
Review Date 1/10/2022
Updated by: John D. Jacobson, MD, Department of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.