If you're on pelvic rest I wouldn't risk it. With it, you can't orgasm at all from anything. An orgasm causes uterine contractions, because an orgasm IS a contraction. As you've read, this can cause miscarriage in women with preterm labour issues or a weakened uterus. If its only to prevent infection that's one thing, but until you talk to them I wouldn't.
This a great question.. I wish someone had replied to u :/