Salam! Honestly la, most of us yang kenal do BTL after delivery, either normal or caesar, because that's when the doctor can do it easily, so it's quite rare to do it beforehand without delivering first. I'd really suggest you chat with your gynae about this one, because they can explain what's medically possible for your situation and whether it's safe to do it that way. Is there a specific reason you're thinking of doing BTL before delivery?