Hi,
Firstly, once you get your AOR, then the processing time will depend mainly on your stream. I mean CEC inland applicants have fastest processing as of now. For FSW outland applicants, it takes around 45 - 55 days to get the first update in their profile, i.e. medicals passed. You can check immitracker for this. This is an average though, varying from case to case. There are chances that you shall get no change in your status for about some more days.
Secondly, I don't know exactly about your case since I haven't heard about pregnant lady cases.
But, The 6 months time starts from the date of AOR. And yet, it's just an estimate for around 80% cases that IRCC receives.
Ref
http://www.cic.gc.ca/english/helpcentre/answer.asp?qnum=673&top=29
There is no guarantee that they will make decision & issue PR in 6 months only. It may be delayed if they find any discrepancy in applicant's profile or have doubts.
Once you get your AOR, all you can do is just sit back and relax. If IRCC needs any extra info from you, they will contact you directly through your MyCIC account.