In case you are an individual Mediclaim policy holder, then any claim related to pregnancy will not be covered. In case your employer has given you a cover under group mediclaim policy, then perhaps they may have taken a maternity benefit cover after paying extra premium. For this you need to check with your employer.
In the event that you had a maternity cover, then you should ask the insurance company for clarifications regarding the repudiation of the claim, else the claim will stand rejected.