Vesicouterine pouch

In human female anatomy, the vesico-uterine pouch is a fold of peritoneum over the uterus and the urinary bladder. Like the recto-uterine pouch, it is a female pelvic recess. It is continued over the intestinal surface and fundus of the uterus onto its vesical surface, which it covers as far as the junction of the body and cervix uteri, and then to the urinary bladder. It is narrowest when the uterus is anteverted rather than retroverted. The deepest point of the vesico-uterine pouch is typically higher than the deepest point of the recto-uterine pouch.

The vesico-uterine pouch may become attached to the uterus, preventing sliding of the urinary bladder past the uterus. This may occur in a third of women who have had a caesarian section, and some people with endometriosis. The vesico-uterine pouch is an important anatomical landmark for chronic endometriosis. Endometrial seeding in this region causes cyclical pain in women of child-bearing age. This pouch is also an important factor in a retroverted uterus, which can frequently complicate pregnancies.

Source : wikipedia
https://en.wikipedia.org/wiki/Vesico-uterine_pouch