F-8.34

If one cannot fully prostrate so that one's forehead touches the ground (N: a pregnant woman, for example), then it is not necessary to stack up pillows on the place of prostration to touch the forehead on them. One merely bows as low as one can.

If one has put a bandage on the foreheads because of an injury that affects all of it, and there is hardship in removing it (O: severe enough to permit dry ablution (tayammum) (def: e-12.9) ), then one may prostrate upon it and need not make up the prayer.