Im wondering how many obgyns see schs in the second trimester end in miscarriage or placental abruption? is this a common or rare occurrence for a fatal outcome as a result of subchorionic hemorrhages? also mine is very small. pregnant with twins?

Subchorionic bldg ? : With twin pregnancy, the occurrence of subchorionic hemorrhage (which is by definition a placental abruption) is more common, especially with "fraternal" twins (two placentas) but does not usually result in miscarriage. Small hemorrhages usually resolve. Twin pregnancies benefit from a consult with a maternal-fetal medicine MD and close followup.