--- O43.021 Fetus-to-fetus placental transfusion syndrome, first trimester

--- O43.022 Fetus-to-fetus placental transfusion syndrome, second trimester

--- O43.023 Fetus-to-fetus placental transfusion syndrome, third trimester

--- O43.029 Fetus-to-fetus placental transfusion syndrome, unspecified trimester