That is very hard in an apartment. No matter how clean YOU keep things, you have no guarantee that the neighbors bother to do the same. I don't look back on my apartment days with fondness. lol
I have a few green cleaning links that I'll post for you.. you might find something there. Since its green cleaning its probably more likely to be safe for you while pregnant. Many of these things I use myself and I'm also pregnant and have had no issues. Do be careful while handlig borax though.. Its natural, but you don't want to risk ingesting it. Wear gloves and don't put it some place where you would potentially handle food.
http://www.care2.com/greenliving/green-101
For that site, I would type in "ant repellent" in their search engine. Maybe the same thing for roaches. I know ants don't like borax, but they may have other suggestions and complete instructions for you.
http://eartheasy.com/live_nontoxic_solutions.htm
I didn't see any formulas on here for bug killers/repellents, but they had some adds for ones you can buy. Perhaps those could help?
otherwise call your landlord, explain that you are pregnant and it needs to be done during a time you will not be home for a long time. Explain that you guys are keeping you place clean and think that they are coming from another apartment (they could also be residual if you just moved in) so maye they can handle this with neighbor's apartments as well. Scrub down your counter tops and you may want to wash anything that would come into contact with food.