Brown discharge 4 days after sex. implantation bleeding?

Maybe: Implantation bleeding usually occurs about 6-7 days after ovulation. While you may have timed intercourse to try to match ovulation, there is always a bit of guesswork in this plan. So timing may not be specific. Usually other early pregnancy symptoms would also occur: nausea, food aversions, etc. If spotting continues, contact your doctor. 5% of women have spotting before normal period.