Good Morning E., before I became preggers years ago I had terrible cramping. The normal otc med's did nothing to relieve it. I don't know what cd27 is so my information is probably way off base. I had cramped badly since I first started my cycles at 13. The only thing I found that worked while I was young were heating pads on my tummy. Then I went to stay a few days with my Grandma, she made me Ginger tea. Regular hot tea with a few dashes of ginger mixed in tad bit of sugar. What it does is opens the vessels that are restricted with clots and allows them to pass or dilutes them. No more cramps.
After I became pregnant and had our first son, i never had cramps again.
Best of everything to you, you OB may have a better idea of whats going on. Cramping while in first trimester is normal, body is going through changes and rearranging things for the babies growth.
Always,
K. aka Nana K to 5 grand kids