I did perineal massage with my first and had not a stitch but I didn't have a stretchmark either so it could be my skin.

This time I have been slack and not done any perineal massage yet. But I also haven't got any stretchmarks yet either.

I think alot of tearing or not can be to do with your carer and your position when delivering as well. If they support the perineum, and you are more upright it can really help. Also if bub is not in too much of a hurry that can help to allow stretching rather than tearing.