An amniotic hook is a plastic instrument rather like a long crochet hook, and is used to tear a little hole in the amniotic membrane surrounding the baby and the amniotic fluid. This is called an ‘amniotomy’ or ‘breaking the waters’ and is done during a vaginal examination by a doctor or midwife.
The hook is actually fairly blunt and shouldn’t come into contact with your baby at all, so there isn’t really any risk that he/she could be harmed.
Mayes Midwifery