it is very unlikely
HI, thanks for using healthcare magic
tests detect the level of HCG
in the urine.This hormone would not be produced if a woman is having a normal menstrual cycle.
If a woman is experiencing a period then she is unlikely to be pregnant unless the bleeding represents an miscarriage
and the test is still detecting the HCG hormone in the urine. A period represents shedding of the lining of the uterus
that has occurred because there is no pregnancy.
IN a miscarriage there would normally be severe abdominal cramps, clots in the bleeding and fleshy products as well mixed in with the blood.
In addition, the birth control implant is very effective , up to 99%.It is rare to get pregnant using this method. Only 1 out of 100 women would conceive with this birth control.
It is very unlikely but if she wants to check, she can either repeat the test or ask her doctor for a blood HCG level which would be more accurate.
I hope this helps,feel free to ask any other questions