When does implantation bleeding occur?

"Implantation bleeding" is usually mild, and occurs 3-5 days after ovulation. If the bleeding is more like a period, and pregnancy is possible, obtain a serum HCG test if your period is delayed, as more pronounced bleeding may not represent implantation, but may relate to a pregnancy outside the uterus (ectopic).

it usually occurs 10-14 days after conception, just around the time of the first missed period and lasts for about 1-3 days , with light bleeding, pinkish brown in color without clots , and minimal cramping , unlike a period . So any heavy, prolonged bleeding with cramps , and associated symptoms of early pregnancy needs further evaluation .