Wow, tough crowd. The short answer is: No, nobody that I’m remotely aware of tailors what I think of as outdoor-oriented clothing聴fleece jackets, rainwear, that sort of thing聴for the pregnant set. Your query suggests there may be a market for it, but I expect that the mothers who are still out there hiking and climbing right up to their due date are somewhat in the minority. Cheers for you, though聴assuming you really feel like doing that sort of thing with a watermelon under your shirt.
My suggestion, then, is to make the best of what you can find. There are avenues to find some base layer-type items that will fit. Check the Mothers in Motion Web site (www.mothers-in-motion.com). There you’ll find a range of maternity wear for active moms-to-be聴shorts, pants, tops, that sort of thing. Not really outdoor stuff, but it could be used in conjunction with non-maternity outdoor wear.
Beyond that, consider buying one or two “up-sized” pieces that at least will fit around you, and can always be used again if you decide to give the new baby a sister or brother. Don’t splurge here聴buy house-brand stuff from REI, L.L. Bean, Lands’ End, or Campmor. You can get a nice fleece jacket at Lands’ End for $50, for instance. That and an inexpensive rainjacket like Marmot’s Precip ($90) will get you halfway there. Alternatively, perhaps the male party responsible for this happy event has some bigger pieces that he will cheerfully loan to you.
Good luck! Send us a picture of the new arrival.