With rank of 6643 it is very difficult for you to get MD medicine and MD pediatrics in Kerala weather you avail the 50% all India quota 50% Kerala state quota but there are viable chances that you can get MS in gynaecology and obstetrics either in other states availing the 50% all India quota or in Kerala itself availing the 50% Street Kota but you might not get in one of the best institutions for which you needed to score and get a rank within the top 5,000 all India
nevertheless you can use the link of the rank predictor and sharing with you to accurately determine which college and stream you have realistic chances of getting into via different counselling
https://medicine.careers360.com/neet-pg-college-predictor

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