Good advice from ZQ; just be sure to clean up any stains with an enzymatic product like nature's miracle to kill the smell entirely.
The cat is feeling very insecure, she doesn't feel like it's her home anymore. She is urinating on the baby stuff to layer her "scent" over the new scent to make her feel more secure. This should get you to thinking about what could be making her feel so threatened. It is obvious to me that your cat feels threatened by the new baby that'll be in your cat's home. That does sound silly, but that's the way a cat "sees" where he lives.
You also "smell" differently to him, from the hormones that your body is putting out from your pregnancy. That also makes the cat feel like his home is threatened. Have you been giving the cat less attention lately, unintentionally? If so, you might want to start making him feel better by giving him some more attention. You can also get a product called Feliaway. It puts out scents called pheromones, that can calm a cat down and possibly make your cat feel more secure. This product comes in a spray form, and a plug in form.
Let me know how things turn out!