I don't like the idea of showers (it's the one way I'm supersticious), so we had "baby welcomings" for both of our kids. The first one we did accept gifts, because we didn't have a shower. The second one we wrote "no gifts" and some people brought something little like bibs or stuffed animals, but I don't think that people spent more than $10, which, in my mind, is about the equivalent of a bottle of wine that I would bring to a holiday party or something. Not a big deal.
Honestly, I'd ask the mom what she wants to do. If she didn't get to have the shower but still needs the stuff that she would have gotten, then I think it would be lovely to host. If she already got that stuff, ask if she'd like to have a party, maybe mentioning "no gifts" or "donation to such and such" instead. It's possible that people haven't come by with gifts at all, and she's really hoping that someone will get her a high chair and a stroller.
Finally, if you really don't want to host no matter what, beg off with some personal excuse: really too busy with XY or Z, Bad date for you, etc. There might be some hard feelings, though. You just have to decide what's more important to you.
Good luck.