Sonogram before Clomid

Amanda 🐼 • With my husband for 19 years, married 10 💍 Postpartum RN 💉 Addison Sarah born 1/1/16 🎀 Baby #2 due April 2019 🤰Obsessed with Glow 🤷‍♀️
Did anyone else have to go in for a sonogram before starting Clomid for the first cycle? My doc told me to call him when AF came, to schedule a sono. He hadn't even given me the prescription yet. And if yes, what is that sonogram for?