I actually think that is a very good sign. Although I've never had IVF, I have seen women on here who have gone through the IVF process, get cramping and I believe I've heard it said that for some reason, it's more common in the IVF process. Not sure if that is true or not.
But with my last pregnancy, I was absolutely convinced I was out because I was getting cramping so much earlier than I normally do before my period. And it started really early. I called my sister who has seven children and she said that was always a telltale sign for her that she was pregnant.
If that cramping is due to pregnancy, it is your uterus actually starting to expand, "knowing," that there is a baby on board. We always associate cramping with something being pushed out and it scares us when TTC. I know it seems silly for your uterus to start expanding because it's a minuscule little thing I'm there, but it's all about what your body is communicating to itself about what is happening in there, and readying itself.
Wishing you best of luck!
