There is no good reason to believe that menstrual cramps and menstrual pain are vastly different than regular cramps and pain. Especially because the cramps and pain are often caused by the same hormonal response. This makes the studies still relevant and useful.
These studies have shown that CBD can help relieve pain and cramps. CBD reduces pain and cramps because it interacts directly with the endocannabinoid system.
The endocannabinoid system is a series of nerves that runs through the entire body. CBD binds to the nerves, which has a pain and inflammation reducing effect. The endocannabinoid system also stretches into the uterus. Inflammation reduction has also been proven to reduce period cramps and pain. Since CBD has anti-inflammation effects, then it makes logical sense that it would work to treat period pain.
No studies have been conducted on the effect of the system in the uterus, but it would make sense that it would reduce. The testimonials from women using CBD to help menstrual cramps certainly confirms the hypothesis.