Termination during pregnancy

Hi, This is V here. I am working in a private IT company since 1.5 years. I got pregnant and in anticipation of support in working hours I have informed the company's HR about my pregnancy requesting relaxation in office hours. However they have put me on Performance improvement plan (PIP) for 2 months. As HR verbally informed me that they are going to put me on PIP, I have mailed HR giving reference of my verbal conversation asking for support mentioning about my pregnancy as proof of informing before PIP and after that same day they send me PIP mail. I requested on that PIP mail to postpone that by one month or so, as my reporting manager (who is Promoter of company) assured me that he is ok with that, but he only denied to HR to Postpone. In short they want to fire me after PIP result so that they need not to give me maternity leave. What should I do...one month of PIP is over and I have not formally accepted that on mail. Pls suggest what should I do? Thanks in anticipation.