Hi Dr., I am 36 yrs old. Very regular periods, 30 days cycle, had intercourse around ovulation last period on 21 September (never had early periods) started light spotting 23 days into my cycle (never had this ever in my life, spotting between periods). It has lasted around 7 days. Done 3 home pregnancy test (one being today) and on Monday 19th I had a blood test with all being negative. If it s not implantation bleeding (as I ve been reading online could be a possibility, what other possible medical reason could it be?