Pregnancy During Your Period: Will Your Period Stop?

If you get pregnant while on your period, your period will stop. This is because the levels of the hormone progesterone increase during pregnancy, which causes the lining of the uterus to thicken and prepare for implantation of a fertilized egg. This prevents the shedding of the uterine lining and therefore menstruation does not occur. However, some women may experience light spotting or bleeding early in pregnancy, which is not menstruation but rather implantation bleeding.