Both my kids were born naturally. My OB says it is probably the ligaments around my uterus that are cramping, and it's not that common, but it's not a cause for concern. If I had that accompanied by bleeding then it would be a cause for concern.
It could also be due to the fact that it's been 8 years since my last pregnancy and I am 8 years older (a fact that people keep telling me and it makes me go crazy...). I was definetly young when my first two were born- 19 with DS and 21.5 with DD. I'll be 30 this October.
Other than those darn cramps, which are getting more and more frequent, I'm also getting nausea again. But I think it's partly to do with the heat wave we're experiencing here in California. It's been 100+ for 4 days in a row.

I'm drinking probably about 2 gallons of water a day and eating tons of cold fruit and popsicles.
The wierdest cramps are the ones I keep getting in my knees!! OB can't explain that either, but attributes that to my age (again) and the fact that it's been so long since my last baby... thankfully, even though my legs are swelling considerably, my BP is still looking good. I'm very worried that I could have problems in these last 10 weeks... AGH! I'm really paranoid this pregnancy.