Hello Neha

This year in states like Tamil Nadu, Karnataka and many others, the DGO (Diploma in Obsterics and Gynaecology) seats have been converted into MS OBG (Masters of Science in Obsterics and Gynaecology). So the MS OBG seats have in fact increased and diploma seats have been decreased by this step of the respective state governments. 

The major difference between DGO and MS OBG is that DGO is a two year program whille MS OBG is a three program. A candidate pursuing Dgo need not submit his thesis at the end of his program while for a candidate pursuing MS OBG has to submit a thesis at the end his three year program.

As long as qualification is considred, both stands equal but a DGO cannot become a consultant at a medical college nor can he go into academic sector and become a professor. As per the Indian Govt. one needs to have a MS degree to become a professor at any college. For that matter MS is preferred and more valueable over diploma and so is the competition ever growing. But both of the candidates can have a normal practice irrespective of their degrees.

Hope this helps.

All the best!