Spotting before period

Anna
Is it normal to have a brown discharge 3-5 days before a period? For the past 5 or 6 months I've been having this discharge like clockwork right before I start. I've been counting the day I begin cramping and bleeding as the start of my period or is the discharge the actual start of my period?  It hasn't bothered me much other than being an inconvenience however my husband and I are going to start TTC soon and I was thinking perhaps I should make an appointment with my OB/GYN to have it checked out.  Any advice would be appreciated. Thanks!