You know, a big reason that I shied away from purchasing a ton of for-real maternity clothing last time I was pregnant was that I simply didn't want to spend money on things that I'd only wear for a couple of months and then tuck away in a storage bin somewhere.
And so what I ended up mostly doing was making sure that the things I did buy were the kinds of flowy pieces ("maternity" or not) that I tend to wear anyway - things that would be looser on me post-pregnancy, but still be the kinds of items that I would genuinely want to keep on wearing beyond when I "had" to.
That's essentially the philosophy behind HATCH: it's clothing specifically created for mothers-to-be - focusing on soft fabrics and comfortable cuts - but chic enough that you won't just "be able to" wear it post-baby...you'll want to.