I found this caution about this form of pranayama in “Luna Yoga” by Adelheid Ohlig; I included a description of the technique for clarification since the sanskrit name was not provided.
"FIREBREATH: This breathing technique stimulates (fires up all metabolic processes. You can do it while standing, lying, sitting, squatting, or crouching on all fours. It has a very deep effect on the reproductive organs. [b]WOMEN WHO HAVE AN I.U.D. SHOULD NOT DO THIS EXERCISE - THE I.U.D. COULD FALL OUT ![/B] (emphasis is mine).
Exhale completely, then pull the diaphragm up under the ribs. Remaining in full exhalation, push the diaphragm strongly down toward the pelvis. Without breathing, move the diaphragm up and down so your entire abdomen shakes in ripples. Possibly you can feel your feel your uterus and other internal organs as they move. When you can’t do this any longer, inhales again. Then take equal time to let your breath come and go in your own rhythm. The Firebreath can be repeated up to six times."