Pregnancy laws.

Hello! I work with an International Private School. I am serving my probation period. I am 4 months pregnant. I informed the school authorities about my state through mail on 1 July 2018. Due to certain medical conditions, I was operated on 2 August 2018 and was asked to go for bed rest through out my pregnancy. As per the probation contract, I have to give a month's notice before leaving the job or pay a month's salary. I asked school management to give me leave (via mail). Instead they have asked me to resign and pay a month's salary with immediate effect (through telephonic conversation by school's office employee). Is it compulsory for me to pay a month's salary?