Interviewing While Spawning - Still Waiting

It's now been 3 weeks, and I feel that my personal situation is distinctly different from what it was 3 weeks ago. I have 6.5 weeks until my due date. Even assuming 1) I get an offer tomorrow (they're calling my references) and 2) I like it and want to accept it, how would the negotiations work out? After I give my 2 week notice, do I then start the new job only 1.5 weeks from my good-to-go date or can I get them to wait to start me until after my leave (like mid-Sept/early Oct). The job is definitely far superior to my current position skills-wise, but I have a number of deal-breaker concerns. 1) The $$ would have to be better to compensate for my commute expenses. 2) My benefits would have to start immediately, can't not have benefits as a pregnant woman. 3) Do I get paid for my leave? Probably not, although I've accrued enough time here... Many things to discuss if I get an offer. What frustrating timing - these things would have been much less of an issue a month ago!

I guess the question is, if they want me, will they be patient and wait for me? And considering (always) the Breadwinner's tenuousness, is it a good idea to commit to something new right now? If my current position weren't going to be seriously altered by the end of the year (for the negative), I'd definitely say 'no'. Plus, I have loyalty to my employers. I wonder if they'd take me as a contract worker for a while until they can find someone else to fill my role...