A chemical pregnancy is a very early miscarriage that occurs typically before the fifth week of pregnancy, often shortly after the embryo implants in the uterus
. It is called "chemical" because the pregnancy is detected only by the presence of pregnancy hormones (human chorionic gonadotropin or hCG) in blood or urine tests, but it is too early for an ultrasound to show a developing embryo or fetus
. In a chemical pregnancy, the embryo stops developing very early, causing hCG levels to rise briefly and then fall, leading to a positive pregnancy test followed by a negative one a few weeks later
. Many people may not even realize they had a chemical pregnancy because it can feel like a late or heavier period, sometimes with mild cramping or spotting
. The most common cause of a chemical pregnancy is chromosomal abnormalities in the embryo, which prevent normal development
. Other possible causes include uterine abnormalities, hormonal imbalances, infections, or issues with the sperm or egg
. Chemical pregnancies are very common, accounting for a significant portion of early pregnancy losses, and most people who experience them go on to have healthy pregnancies
. Typically, no medical treatment is required, although some may experience heavier bleeding or cramps during the loss
. In summary, a chemical pregnancy is an early miscarriage detected by pregnancy hormone tests but before ultrasound confirmation, caused mainly by chromosomal issues, and is a common and natural occurrence in early pregnancy loss.
