I'm hoping to become pregnant soon. what would a "safe" sweetner be?

I'm 38 so I know there are higher risks for me as it is. I've gotten off my bp meds. But I have to continue to exercise to stay off.

I gained over 90lbs with my first and 70 with my second. I lost almost 100 before having my second one. I can't do that again to myself or my child. LC is the only way I will attempt to have another one.