Sigmoidocele (also known as Pouch of Douglas descent) refers to a condition where the sigmoid colon descends (prolapses) into the lower pelvic cavity.  This can obstruct the rectum and cause symptoms of obstructed defecation.
The phenomenon is caused by a weak section of fascial supports of the vagina (the uterosacral cardinal ligament complex and rectal vaginal septum), which allows a section of peritoneum containing the sigmoid colon to prolapse out of normal position and fall between the rectum and the vagina.
Sigmoidocele normally occurs in females, and is uncommon. 
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