Implantation bleeding can be one of the earliest pregnancy
symptoms. About 6-12 days after
conception, the embryo implants
itself into the uterine wall. Some women will experience spotting as well as some cramping.
Other Explanations: Actual menstruation, altered menstruation, changes in birth control pill, infection, or abrasion from intercourse.
Delay/Difference in Menstruation:
A delayed or missed menstruation is the most common pregnancy symptom leading a woman to test for pregnancy.