This particular bleeding typically occurs 10 to 14 days after ovulation and is usually much lighter than the normal menstrual period. At this time, many women expect their normal menstrual period, so this bleeding can often be confusing. As a result, early pregnancy can also be missed. In addition, problems can arise when calculating the gestational age if this bleeding is used as the "last normal menstrual period" for the calculation. The first ultrasound then shows that it was an implantation bleeding and not a monthly bleeding and the gestational age is corrected accordingly.
The implantation bleeding only lasts a short time and does not require any special treatment. If you are unsure, a pregnancy test will immediately provide certainty.