A biochemical pregnancy is an early pregnancy loss that occurs shortly after implantation. Biochemical pregnancies can account for 50 to 75 percent of all miscarriages.
Biochemical pregnancies occur before ultrasound can detect a fetus, but not too early for a pregnancy test to detect levels of BhCG, or beta human chorionic gonadotropin. This is a pregnancy hormone that the embryo creates after implantation.
The exact cause of a biochemical pregnancy is unknown. But in most cases miscarriage is due to problems with the embryo, possibly caused by poor quality sperm or eggs.
Other causes may include:
- Abnormal hormone levels
- Uterine abnormalities
- Implantation outside the uterus
- Sexually transmitted infections
- Being over 35 years of age increases the risk of a biochemical pregnancy
- Blood clotting and thyroid disorder