Will implantation bleeding continue to come each month like a normal period or will it happen only in that first month if a girl is pregnant?

Sometimes both: For some women, they have some implantation bleeding at around 5-6 weeks, and then no bleeding. Other women have no bleeding at 5-6 weeks, but then have some spotting later on. Still others can have spotting on/off. Bottom line, 25% of all women experience some form of first trimester bleeding. Discuss with your doctor if you bleed, especially if you bleed like a period.

Once-but can spot: Implantation bleeding occurs just once. At the time of implantation when the fertilized egg implants or attaches itself to the uterine lining. If there is spotting or bleeding during a pregnancy beyond this time period- then i recommend eval by the dr- this can be sign of threatened miscarriage- improper placement of placenta, infection or other issue.