I think my midwife tests me for drugs at all my appointments...

So the only time I've seen drug test strips are in the reality show "Dr Drew " and they look quite unique because they are like the regular small strips but they have like 6 squares or something on them. And I've only had 2 visits with her so far and she's used these test strips both times when testing my urine. I wonder if this is a normal practice? I'm also a little curious if she's doing it bc my first child was born small (5lbs)  for no known reason. I don't mind because I don't do drugs, I would never in a million years do drugs while pregnant. I don't even take Tylenol(or any Otc drugs),  drink coffee, or anything of the sort while pregnant. I can't help but feel slightly offended though.