Pick a job that offers actual maternal leave (teaching's probably the best—time it right and you get the Summer, too, plus your daily schedule will be close to that of your kid so you'll have lower daycare costs) or otherwise is either fairly tolerant of people disappearing for a while for kids or is easy to get back into after leaving—I don't have direct knowledge of this but I suspect family-friendliness and relative ease of relocation to follow a higher-earning spouse, say, is part of the appeal of all of teaching, nursing, and real estate agent..ry? ing?

Or just take barely enough unpaid leave (or draw on other pools of paid leave, which are usually tiny anyway and may have been eaten into over various pregnancy-related issues and appointments already) to get back on their feet and head back in, leaving the baby with a cheap unlicensed daycare down the street (maybe fine, maybe, uh, not, but not like there are other options on a limited budget) or older relative or whoever :-/