Aidyn never fully engaged at all... in fact at my 39week appt, the midwife said to me that I would be going overdue and to book ahead for my induction. Well, she was wrong and my waters broke the very next day. I'm pretty sure up until I gave birth he never engaged more than 2/5 (maybe cause his head was so bloody big?), yet I had no problems with the birth or him fitting through my pelvis... so I guess it is very different in each individual case.