A period is a menstrual period. Normally, a woman has a normal period and pregnancy can be ruled out. If a woman has normal menstruation for two months in a row, but she is found to be pregnant, it means that the second period may not be a real period, but abnormal vaginal bleeding, such as bleeding from implantation, pre-eclampsia, biochemical pregnancy, etc. 1. Bleeding from implantation: After a woman has sex, the fertilized egg usually implants within 7-10 days after intercourse, and some women may have vaginal bleeding, which may be mistaken for menstruation; 2. Pre-eclampsia : Due to luteal insufficiency and embryonic dysplasia in pregnant women, it may lead to pre-eclampsia miscarriage, which may be accompanied by symptoms such as back pain and lower abdominal pain in addition to vaginal bleeding. It is recommended to go to the hospital for gynecological ultrasound, blood test for HCG and progesterone, and if necessary, fertility treatment; 3, biochemical pregnancy: biochemical pregnancy is not a real pregnancy, but there will be pregnancy manifestations such as elevated HCG, and the main manifestation is vaginal bleeding.