Did the decidual bleeding usually occur during the time when you have your mentruation period?

Same answer : Implantation bleeding/decidual is not really as common as the internet would have you believe. When it does happen it's usually 6-12 days after ovulation and exclusively in pregnant women. A pregnancy test 7-10 days after unprotected intercourse is much more helpful to determine the cause. If the test is negative then it's just a period