Would there be pain with minor placental abruption ?

Maybe.: Placental abruption is most likely in the last 12 weeks before birth. Classic signs and symptoms of placental abruption include: vaginal bleeding; abdominal pain; back pain; uterine tenderness; rapid uterine contractions, often coming one right after another.

Not always: Pain is a symptom of placental abruption, however, not every patient experiences it. Sometimes chronic abruptions can present with only bleeding or even without symptoms.

Sometimes: Abruption is a bleed from the placenta; a disruption of either the mother or baby's blood supply. Many causes: trauma, high blood pressure, drugs (cocaine), preterm labor, polyhydramnios. Can be very large or very small, so even US can miss a diagnosis. Symptoms: usually preterm contractions, sometimes vaginal bleed. Fetal monitoring is necessary. Wait, watch; abruption can self-heal sometimes.