I find this show incredibly depressing/infuriating, and I can only hope that teenagers who watch it are getting the same message I am: your expectations for your deadbeat boyfriend are totally unreasonable. I don't think it glamorizes teen pregnancy at all.
Anyway, I happened across an article about the show that showcased a novel criticism. Jami Quesenberry, mother of eight, says of 16 and Pregnant:
I found those shows so depressing that I am afraid they may encourage abortion . . . The one girl who responsibly decided to put her baby up for adoption, at least in the episode I watched of ‘Teen Mom,’ was still depressed with her decision after five months . . . The other mothers [on the show] had lives that seemed stifling . . . If a teen watched that show, she may decide to terminate her pregnancy rather than go through what these teens are going through.Well played, madam. Quesenberry has blocked the show in her home, presumably so that her eight children don't get the wrong idea about teenage pregnancy being all depressing and shit.