A 22-year-old female presents with vaginal bleeding and a dilated cervix at 12 weeks of gestation. What is the most likely diagnosis?

The diagnosis in this scenario is most consistent with an inevitable abortion. In this case, the patient is 12 weeks pregnant and presenting with vaginal bleeding alongside a dilated cervix. These signs indicate that the pregnancy is unlikely to continue; the cervix being dilated signifies that the body is actively preparing to expel the contents of the uterus.

An inevitable abortion typically features cervical dilation and vaginal bleeding, suggesting that a miscarriage is about to occur, but not necessarily that it has already happened. The key aspect here is the combination of cervix dilation with bleeding, indicating that the pregnancy cannot be maintained.

Other conditions, like a threatened abortion, would likely present with vaginal bleeding but without cervical dilation; the pregnancy might still be viable, and the risk of miscarriage is present but not imminent. In the case of an incomplete abortion, some products of conception would have already been expelled, but the cervix would remain dilated as well. A complete abortion would show that all products of conception have been expelled, with the cervix often returning to a closed state, typically without ongoing bleeding or dilation. Therefore, the combination of symptoms in this patient points towards an inevitable abortion as the most likely diagnosis.