Bombay HC had denied her plea to abort her 25-week-old-foetus, which had a congenital heart problem.
Niketa was rushed to a hospital in suburban Mumbai after complaining of severe pain on Tuesday night, her husband Haresh Mehta confirmed.
He blamed the constant media pressure for his wife's high blood pressure and increased stress level, and claimed that this had resulted in the miscarriage.
The court had ordered a special committee from JJ Hospital to give an additional confirmed opinion. JJ Hospital had said then that the chances of the baby having the ailment were bleak and the foetus had least chance of having a congenital handicap at birth.
The Pregnancy Act of 71, the country's 37-year-old abortion law does not allow the termination of pregnancy beyond 20 weeks unless it has the potential to harm its mother's life or health.