Gwen & Gavin haven't confirmed, but everyone's reporting on it. She's 43, he's 47 and they have Zuma and Kingston. If it's a girl maybe they'll name her Kaya London or some other interesting combo of place and Bob Marley reference. (Kaya is a Marley album).

My favorite report about her possible pregnancy is from Michael K over at DListed:

"Gwen Stefani will bare her midriff through a snowstorm, a hailstorm, a Sharknado and every other kind of storm. I’ve seen Gwen Stefani’s midriff more than I have see my own (which is a good thing since mine looks like a shaved and half-deflated baby sloth taking a nap on pizza dough). We haven’t seen Gwen Stefani’s midriff in at least 9 seconds and she’s been covering that midriff up, so that totally means there’s a fetus in there."

http://dlisted.com/2013/09/04/gwen-stefani-might-have-a-case-of-the-babies/

http://www.usmagazine.com/celebrity-moms/news/gwen-stefani-pregnant-expecting-third-child-with-gavin-rossdale-at-age-43-201349