I have been offered a very part-time job for a charity. The salary is way way lower than what I am used to but I went for it because it was handy and local and the people seem nice.
My issue: I am actively trying to get pregnant (fingers crossed I may be already). I won't start the job until January. Am I being unfair to them to take this job with the intention of leaving and then them having to rerecruit all over again (I wouldn't return to it if I took maternity). Or since they are paying me peanuts and know they are getting a total bargain (they admitted this) should I just go for it.
Morally I feel mean and feel they may be angry with me once I start and then fess up (assuming I am successful getting preggers) but I could do with five or six months of pocket money. 
I remember when I didn't have kids I recruited a manager who then admitted she was pregnant and I felt very betrayed that she'd taken the job
and that I had turned down good candidates although admittedly here this is a very junior role.