ok- what i'm gathering is that this is usually due to excessive scar tissue (either due to multiple previous births resulting in tears that built up over time, keloids forming on a scar, or FGM) ... in this particular situation (and I do realize this view may not be popular here) I personally would go with a small planned episiotomy to prevent excessive tearing and rupture- in severe cases such a tear involving that much scar tissue could tear uncontrollably into the anal cavity (and is more likely to than your average natural tearing due to the rigidity of the scar tissue) while a natural tear may heal better than an episiotomy, in this case, and episiotomy is more controlled and could potentially keep the tear from becoming unnecessarily too large (and although that may not turn out to be the case- having the odds in favor of not having an unmanagable tear is good enough for me) but a vaginal delivery is still most certainly possible :)