Smoking Marijuana while Pregnant in South Carolina

Hey guys! I'm 9 weeks and 1 day. I currently live in South Carolina. I'm not a new OB patient. I smoke marijuana once a day (2 puffs maybe) to help me sleep (diagnosed insomnia). I'm worried that my office has been drug testing me without my consent. In South Carolina, do they have to have consent during pregnancy to drug test? I do know they drug test once the baby is born. Please no bashing. Thanks!