Pink spotting

Hi everyone, this is my first post. My husband & I have been ttc for 4 months and had intercourse during our last fertile window but today I had light spotting which was pink in colour. It only happened once & I was clear the next few times I went to the bathroom but just wondering if this is any indication as to whether we have conceived or not? My period is due in 4 days. Any help or experience would be great! Thanks!