I've heard many different opinions, but I don't think that it is ever safe to ride pregnant. Horses are unpredictable animals so anything could happen. Say your horse unexpectedly spooks and you fall off, you could risk losing the baby. If you ride, it can be risky and there are no guarantees with horses.

During the beginning of my friends horse pregnancy we rode light, just mostly walking. As she got more into her pregnancy the riding was at a very minimal we just let her stretch her legs in a pasture, no stress on her and let her feel of mother hood. I wouldn't recommend heavy riding at all.

Ask your Dr and follow their advice. Personally I dont think it is a wise option. Pregnancy effects your balance big time. And even the best horse can be unpredictable at times.

I think you and the horse Just take some R&R...one year off to have a happy child or colt is not 2 much to ask for..

Oops read the question wrong, I agree with everyone, take sometime off the risk of losing your baby is greater because anything can happen when your riding even on a very calm horse. Enjoy your pregnancy and take care of yourself. You'll have plenty of riding time after the birth of your child. Your horse will understand.