Why is Ten Centimeters the “Magic” Number?
I once had a teacher who said the cervix actually dilates to 13 cm but 10 was a better number so we use that. You are so right about the “non-magicness” of ten cm dilatation. For one thing, it is very subjective. Just ask two providers to check the same woman. After four cm, the discrepancy gets higher and higher as labor progresses, then gets better toward the end of first stage. At this point, they are judging how many cm there are left. I know some midwives who try not to check women in labor when they first feel the urge to push. They are waiting for the woman herself to tell them when they are completely dilated. And just because a woman is “complete” does not mean she is ready to push. Rotation of the baby, psychological and emotional status of the mother, position of the mother – all have a part to play in “readiness.” If all is going well and there is no indication for haste, it is best to let the mother push when and if she wants to. She will generally start with some tiny pus
