A chemical pregnancy or a very early miscarriage occurs when a pregnancy is lost shortly after the implantation which also results in heavy bleeding. When a fertilized egg implants in the uterus, cells that would become the placenta begin to produce the levels of the pregnancy hormone hCG and these hCG levels are high enough that they are able to be detected on a blood or a urine test and can create a positive result on a pregnancy test. However, an ultrasound would not be able to detect a gestational sac or a placenta developing and an ultrasound could not detect a heartbeat. The fertilized egg does not complete implantation and loss of pregnancy occurs which also results in bleeding about a week after your regular period were due during a chemical pregnancy.
Because chemical pregnancy occurs early in a pregnancy, women may not even realize that they have conceived when they experience a chemical pregnancy. The following may be signs of the chemical pregnancy such as heavy bleeding, menstrual like cramps, passing clots from the vagina, etc. The reasons for the miscarriage vary but most occur because the fetus is not developing normally and errors with genes or chromosomes usually occur by chance as the embryo divides and grows. Experiencing heavy bleeding around the time of your expected period soon after receiving a positive result from a pregnancy test can be a sign that you are no longer pregnant. Other causes may include the following such as inadequate uterine lining, low hormone levels, luteal phase defect, infection, etc.