Shoulder pain is common in ectopic pregnancies due to a phenomenon known as referred pain. When an ectopic pregnancy causes internal bleeding or the fallopian tube ruptures, blood may irritate the diaphragm, which shares nerve pathways with the shoulder. This can lead to pain felt in the shoulder, even though the source of the problem is in the pelvic region. It is important to recognize shoulder pain along with other symptoms of ectopic pregnancy for prompt medical attention.