Will a prenatal massage help with cramps?

It really depends on the practitioner and what style of prenatal treatment they are giving. I am not sure whether you are pregnant and dealing an uncomfortable new pregnancy or if you are not pregnant and just looking for relief from monthly menstrual symptoms.
For either situation, I agree with my colleagues that working on the lower back (ie. lumbar area), the sacrum (the triangular bone located just below the lower spine) and the gluteus muscles can decrease cramping.
For relief from monthly menstrual cramps, Maya Abdominal Massage, breath work and yoga are fantastic for creating healthy, pain free cycles.