1. What is pregnancy biochemistry? Pregnancy biochemistry refers to the situation where in the early stages of pregnancy, although the urine pregnancy test paper shows positive, there is no embryo or embryo in the B-ultrasound examination. This condition is also known as \”vacuoles\” or \”vacuoles.\” 2. Causes of pregnancy biochemistry 1. Chromosomal abnormalities: Chromosomal abnormalities in the embryo are one of the main causes of pregnancy biochemistry. 2. Maternal immune problems: Abnormal maternal immunity may attack and destroy the embryo. 3. Hormone level problems: Insufficient or excessive hormone levels may lead to biochemical pregnancy. 3. Biochemical symptoms of pregnancy 1. Vaginal bleeding: