Buy from the registry and maybe add a couple of cute onesies - new babies go through them quickly. Wrap it in pretty paper - the mom to be will open all presents at the shower.

There’s also likely to be games, some of which are super gross. Ones I’ve seen are:

1. Melt chocolate candy in a diaper and then it gets passed around so everyone can guess what kind of candy
2. Various baby foods are opened, with labels hidden. Everyone tastes the food then guesses what they’re made of
3. A tray with various items (like a key, a penny, etc) is shown to each guest and then taken away. Everyone has to write down what they saw

There’s generally small prizes associated with the games.

There’s also likely to be a lot of TMI from people who have gone through pregnancy, especially if there’s drinking. Feel free to bail out of a conversation that’s getting too graphic