I had a friend, mid-thirties, miscarry her first baby. The doctor told her to wait a few months to give her body a rest. She wanted to wait because it had been traumatic emotionally, and she wasn't ready to risk that just yet. Well, she and her husband are not good at birthcontrol. She didn't get her next period, and she delivered a beautful baby girl nine months later.
Every woman is different.
If you are ready to try again and your body is healthy, I say go for it. My doctor advised waiting 2 periods. Luckily, my period started exactly 4 weeks after. So I waited 2 cycles and started trying again. I took his advice.