Were you taught in prenatal class how not to get uterine cramps during labor?
In the prenatal classes I took, they taught us how to completely relax so the uterus does not cramp during contractions. It stems from the Grantly-penis-Reed method. It is how to prevent the fear-tension-pain syndrome. Did the classes you took teach this?
I have had four natural births and what I was taught really works.
They teach that uterine cramps and uterine contractions are two completely different things; as different as a leg cramp and tensing your leg muscle. Labor still is not painless, the cervix stretching is a dull ache.
Muscles can tighten without cramping. You don't have to have repeated charlie horses in order to give birth.
Besides, I have had four kids, so I know it is possible. True natural childbirth classes have a 90% success rate of unmedicated births.