A friend of mine was recently telling me about how her period was causing her significant cramping, up to the point that when she arrived at work one day, she was told to go home and rest due to the severity of it ie. about to puke in the office.
I would imagine this is more of a short term use as needed subliminal.
There is always the pain relief programs. General Pain Relief V10 has been tested on, and is known to work well for menstrual cramping in testing. The free version should also work, but will take a lot longer to kick in.
Cramping is like the cervix muscles acting a bit like the birth process - expelling blood like expelling a baby.
I think it's a bit more involved than that. The entire musculature of the uterus contracts when a woman has menstrual cramps. The cervix itself really has no muscles, if I remember correctly, it's just very dense tissue. And I'm pretty sure the birthing process is a whole different set of muscles and contractions. Regardless, GPR will very likely help.