Final answer:
Hemoperitoneum associated with ectopic pregnancy is most definitively identified through laparoscopy, which allows direct visual inspection of the reproductive organs and the presence of blood in the abdominal cavity.
Step-by-step explanation:
Hemoperitoneum associated with an ectopic pregnancy is identified through a variety of diagnostic methods. While pelvic ultrasound is frequently used to visualize the pelvic organs and can often detect free fluid or blood associated with a ruptured ectopic pregnancy, sometimes the details are not clear enough for a definitive diagnosis. An abdominal CT scan can also provide images that may show hemoperitoneum but is less commonly used during pregnancy due to radiation exposure concerns. Hysterosalpingography is typically used to assess the patency of the fallopian tubes and is not indicated for the diagnosis of acute conditions like ectopic pregnancy. Laparoscopy, which involves inserting a tiny camera into the abdomen through a small incision, is the most definitive way to diagnose conditions affecting the reproductive organs, such as ectopic pregnancies, and associated complications like hemoperitoneum.