Brown Discharge?

I'm 26 weeks pregnant, and I went pee late last night after I spent the day coughing really bad and I had some light brown discharge? It hasn't happened since, but I was just wondering if anyone else has had this happen? I have no cramps or anything and my LO is still moving as normal. 
Side note:  I'll of course call the DR if it happens again and be mentioning this at my appointment Thursday.