Hannah - I had mid cycle spotting once before. Perhaps was a coincidence but I also had a bad case of thrush the same cycle so I think my cervix was a little sensitive (the spotting appeared after bd). It's not abnormal to experience this (sometimes it's due to hormones) but if it keeps up tell your doctor. Like anything Gyno there could be a million reasons why it happens - but don't panic as I said it's not uncommon.