Does the approved pregnancy leave (for 2-3 months) (employer will grant non-paid leave) from the employer affects the H1B status, when one is not leaving the country?? If yes, what needs to be done.?

u should b able to take any leave that is available to full-time employee. there should not be any variation as to whether you are H1-B or non-H1-B...

if there is such a discrimination. you can contact local labor department with documentation of denial of maternity leave. plus the corporate policy..

hope this helps...

As long as there's employer/employee relation i.e if they don't fire you; you can take any leave and can even go outside of US with no problem. I've done it and i know a lots of people who've done it.
congratulations btw