Which finding is most likely to confirm the diagnosis in a woman presenting with left-sided pelvic pain and vaginal bleeding?

The presence of an extrauterine gestational sac with a yolk sac on ultrasound is a definitive indicator of an ectopic pregnancy. In this scenario, where a woman presents with left-sided pelvic pain and vaginal bleeding, these symptoms raise a suspicion for ectopic pregnancy, which commonly occurs when a fertilized egg implants outside the uterus, often in the fallopian tube.

When an ultrasound reveals an extrauterine gestational sac accompanied by a yolk sac, it provides robust evidence of an ectopic pregnancy. This finding can confirm the diagnosis, particularly in the context of the woman's reported symptoms of pelvic pain and vaginal bleeding. The yolk sac is a key structure that supports the developing embryo and signifies that an ectopic gestation is ongoing. Such findings warrant immediate medical intervention, as ectopic pregnancies can lead to significant complications.

Other options, while related to the context, do not offer the same level of definitive evidence for the diagnosis of ectopic pregnancy. For instance, an abnormally rising beta-human chorionic gonadotropin (hCG) may indicate a pregnancy but does not specify the location. The presence of an extraovarian adnexal mass or intraperitoneal bleeding on ultrasound can suggest complications, but again, does not