But babies heads are made up of 4 movable bones which move and mould into shape even in big babies. Much has to do with the labour. Sometimes baby's position can be a problem if the head is deflexed or something but this is not that common... birth is designed to work for the survival of our species and we've done pretty well so far! There truly aren't as many obstacles as your doctors would have you believe. Just need to keep active and get off the bed and avoid drugs or inductions.

Small Pelvis? Here's The Truth About Cephalopelvic Disproportion (CPD)