As far as I know this will be the start of maternity leave as you will be induced. Hospitalization Leave will only be given if you are on long medical leave for other health reason to which you are not able to go work in a long run.
I have also posted in SGH but the doctor says they can only issue HPL for me when i am warded to be induced for 3 days. Maternity leave starts once i have given birth.
It will be considered as Start of Maternity leave my dear. They will also state the date you deliver on the ML. All the best to you💪🏻💪🏻💪🏻.