The main symptoms are vaginal bleeding and mild abdominal pain. The vaginal bleeding occurs around 7 days after ovulation, when the fertilized egg starts to implant, which is basically the same time as the usual menstruation, or a little earlier. If you are not careful, you may think that your period has come early. If you look carefully, you may also find pregnancy material in the menstrual blood. However, there is no need to worry even if it is not found, because a biochemical pregnancy is really similar to a normal period, and it ends when the bleeding clears. Because the symptoms are very mild, you can usually have sex after the bleeding is completely over.