Menstruation does not usually occur in the month of conception, but the fertilized egg may rupture a small number of blood vessels in the uterine lining causing a small amount of bleeding.
Menstruation refers to the cyclical shedding and bleeding of the endometrium that accompanies the ovarian cycle. After conception, when the fertilized egg is deposited, the lining of the uterus does not continue to shed and bleed, i.e., menopause.
Cessation of menstruation is the earliest symptom of pregnancy. A healthy, sexually active woman with a normal menstrual cycle should be considered to be pregnant if her menstrual period does not occur for more than 10 days or more. Early pregnancy may also be accompanied by digestive disorders, nausea or vomiting.
If heavy bleeding suspected to be menstrual occurs even after conception, prompt medical attention is recommended.