it completely depends on how your pregnancy progresses and what your doctor advises you.  if you're in a small city and don't travel too far for work then you can work till the very last week of the 9th month like I did

I took leave from 6th month as I have to travel in crowded metro for 1 hour and I find it risky

It varies case to case.  If in your case travelling is hectic or tiring then I would suggest from 8th month.  If travelling is convenient then you can continue till 9th month.  Also,  discuss with your gynae about it. She is the one who knows your pregnancy better. 

Jst c how ur Pregnancy period goes in case u think 7th Mai possible nai horaha hai toh  7th Se Lelo no problem Ideally I have seen 9th strat hote Se he lete Hao ladies.

actually koi kehta hai ki 7 me lo ,koi 8th me lo. kuch samajh nai a <u>raha</u>