One of the girls at my barn is a little over 7 months, but barely showing. And she rides 3 days a week, usually. She knows her horse, and won't ride anyone elses at the moment.
I'm in the process of trying to find out if I'm pregnant (1st test was confusing, taking another tomorrow.) But right now this nausea is what is keeping me from riding. I feel that as long as you know your horse, and you don't do anything stupid like jumping creeks, you're ok.
~*~Never approach a bull from the front, a horse from the rear or a fool from any direction. - Cowboy saying~*~