Degenerating uterine fibroid

Ectopic pregnancy is a complication of pregnancy in which the embryo attaches outside the uterus. Signs and symptoms classically include abdominal pain and vaginal bleeding, but fewer than 50 percent of affected women have both of these symptoms. [Source: Wikipedia ]

Degenerating fibroid
Degenerating leiomyoma
May Cause
Endometrial fluid
Prominence of central uterine echo