You can consult Dr.Sridevi..Her clinic is somewhere near station road..Also she does a consultation at Raju hospital, T.Nagar..I have heard she is very good though I do not have any personal experience
Dr. M. A. Lakshmi is one of the best gynec in T. Nagar area. Her clinic is "Gunasekaran Nursing Home", #1, Cresent park road. t. nagar. Her consulation timings are 10 am to 1 pm and 3 pm to 5 pm from Mon to Sat except Wed evening. Though this is not exactly located in west mambalam, the clinic might be somewhat nearer to your area. I had my first delivery there. Best Wishes!