13 month bonus

In the year of 2019 I worked till November first week and went into hospitalization leave till 2020 Feb (till I due for birth) after that only I'll be taking my maternity leave and will require me to go back to work mid June of 2020. I didn't get any amount of 13th month bonus but have been receiving my pay during my hospitalization leave. My hospitalization leave for 2019 is 54 days when I'm entitled to 60 days. This year 2020 I'm on hospitalization leave for 45 days and my leaves got renewed. Is it normal for companies not to pay 13 month bonus if their on hospitalization leave? Can anyone advise me?