Cute maternity clothes?

I'm not sure if this is what you are looking for, but what they have done is made a few of the items in CAS available for maternity.
http://thumbs.modthesims2.com/img/3/2/1/6/5/9/6/MTS_CmarNYC-1116288-Screenshot-8.jpg
http://modthesims.info/d/404879

Buckley sims has added pregnancy morphs to Late Night and University clothes.

I found some cute things on TheSimsResource(dot)com just by using "maternity" as my search parameter under TS3 female clothing.

There are a bunch from PoppySims: https://web.archive.org/web/20150316124339/http://www.poppysims.com/index.html