I have ridden mares up till 9 or 10 months without any problems. I was only riding for an hour or so but I made no concessions for her condition. I have ridden mares with the foal a week after foaling. You have to be careful that you don't overwork the foal and remember that the mare may still be a little week from foaling. If you wanted to wait 2 weeks there would be no problem.