HELP!! Cats peeing on my stuff since being pregnant!

Needing so help. I've had my cat for about 5 years. He's peed on things before randomly but not continuously. The past two weeks he's peed 4 times in the same spot where my shoes have been sitting. & it's only on my shoes, not my husbands. We've scolded him and he knows he's in trouble right when we find it. I don't think it's due to a medical problem, I truly believe it's because he senses my pregnancy hormones. Has this happened to anyone else? What can I do?