Vaginal delivery can be allowed in all of the following conditions, EXCEPT:
Mentoanterior face presentation, extended breech and dichorionic twins with first veex and second breech, all these can be allowed for vaginal delivery. The clinical indications for elective caesarean section in twin gestations includes a non veex first twin and monoamniotic twins. Complications of monochorionic monoamniotic twinning: Besides cord entanglement these twins are at greater risk of conjoining, preterm bih and twin-twin transfusion syndrome (TTTS).
Monochrionic, monoamniotic twins
Mentoanterior
Extended breech
Dichorionic twins with first veex & second breech