Can my doctor do this?

I had a c section a month ago. When I was in the hospital my family was present. My step mom is also a patient of my OB's when he saw her in my room she explained to him how we were related. A couple weeks later I had to cancel an appointment at my doctors office and when they could not reach me for a few days they called my stepmom and discussed my incision along with insurance and billing information. My step mom is not someone on my paperwork to be contacted for any reason only my husband is. He only got her number from her medical chart. Can he discuss my medical issues with someone without my consent???