The biggest risk to oral contraceptives has been on clotting.

Blood clots remain as serious. If you smoke, now is the time to quit if you choose to use BCs.

If you take them for cramping only, you might try what worked for me.

Over 10 yrs ago I started to fix an essential fatty acid deficiency our whole family (and much of America has) had.
I did this for other reasons, but one thing that improved was
the monthly cramping.

I had this very badly, because I also had PCOS.

This is how it works...
Our bodies make several types of internal signaling compounds called cytokines. The Cox-2 type are called inflammatory or stress/healing oriented. They come from our food containing Omega-6 fatty acids (from soybean oil, sunflower etc). The Cox-1 series come from Omega-3's found in flax oil, walnuts and canola oil.
Our bodies' need both, but work best with a certain ratio
1:1 or 1:5 max for Omega-3:Omega-6.

Typical American diets skew this ratio to more like 1:25. This was found to be the case for kids with ADHD, and now we know that by increasing Omega-3 for them, the ADHD, and their dry skin improves.
When I changed our foods and removed transfats from our diets, I, my son, and husband improved greatly from daily issues of discomforts/disorders.
My GERD went away, my asthma cleared up (now only on emergency basis) and my cramps minimized to almost nothing.

This is how Naproxen and Ibuprofen work for cramps. They are Cox inhibitors that block the action of cytokines on the uterus.

Here is a more detailed description of the system:
http://www.patentstorm.us/patents/62...scription.html

On that link is a suggestion that the amino acid histidine can help. This I don't have first hand knowledge about, but the chemistry described on the patent application is correct about the PGE2 series cytokines causing cramping.
I looked around in my favorite sites (ones I trust) and I could not find verification that histidine would help .. that is...no research papers yet.

But you may be able to change your diet enough to minimize cramping so you won't need the B/Cs. The advantages you would also realize in other health areas would be good for you too. So keep that in mind.