A physio advised me to use a Mimos Infant Pillow to help treat moderate plagiocephaly. Guidelines state that no pillows should be in the sleep space. How has this product been TGA approved and why is it being recommended?

Red Nose recommendations for preventing altered head shape include tummy time when awake, altering baby’s head position when sleeping & supervised & minimising the amount of time baby spends on their back when awake.
There may be a small number of babies who require intervention (eg helmet) to reduce plagiocephaly.
https://rednose.org.au/article/babys-head-shape

How old is your baby?
How does your baby go with tummy time?
Are you increasing the frequency?
Did the physio give any information about the risk/effectiveness of a pillow?

Some physiotherapists and chiropractors have recommended the use of a pillow to relieve the flattening a baby’s head, a relatively common condition, known as positional plagiocephaly. This is not suitable while baby sleeps unobserved. If baby’s medical practitioner recommends the use of a pillow during unobserved sleep, it is recommended the medical practitioner puts this advice in writing.

https://rednose.org.au/article/pillow-use