How long does it take to fleet babies system of marijuana ? I smoke consistently . I stopped long enough where my initial ob screening was clean . I’m unsure how MN works if they test every mom and baby after birth or if it’s case by case...on that note don’t want to deal with CPS and make sure me and baby are clean . I’m currently 14 weeks am I safe to use up to 20 weeks when the first meconium is produced and then stop ?