Ectopic Pregnancy can establish in all of the following areas, Except:

The peritoneal cavity is the space between the membranes that line the abdomen and pelvis. It contains the stomach, intestines, liver, and other organs. 
An ectopic pregnancy happens when a fertilized egg attaches outside the uterus and starts to grow there. The most common place is in a Fallopian tube, but it can also happen in the ovary, abdomen, or the lower part of the uterus (the cervix).