According to Baby Centre, miscarriage can occur at any time after conception. An early miscarriage is the loss of a pregnancy in the first 12 weeks. Up to 75 percent of fertilized eggs are lost in the first days of pregnancy.
After a positive pregnancy test, the chance of having an early miscarriage drops down to 20 percent.
Baby Centre claims that this type of miscarriage typically happens when the embryo is not developing as it should be, possibly due to problems with its chromosomes. The most common side effects of early miscarriage include heavy bleeding and intense cramps. In most cases, no hospitalization or further treatment is needed.