Hi Gigi - I am about 6 months along now and was finishing meso 3 through about the 10th week or so of pregnancy. I spoke to my doctor about the program, and given my fitness level, he said it was fine to continue, but to modify as appropriate and to use my head - I think his exact words were "if it hurts, DON'T DO IT
." During that time, I don't think I increased my reps to 90% during week 3 of the cycle.
I will say that Cathe has said that STS is not intended for pregnant women, as it promotes increased fitness and requires additional exertion and pregnancy is a time to maintain, not increase strength and fitness gains. That said, as this was my 3rd round of STS, I felt okay finishing off the program with slight modifications, being careful not to overheat or strain myself.
I would definitely check with your doctor to be sure and make any modifications as appropriate.
Wishing you a good pregnancy.
Hope that helps.
Reena