The reason for hcg non-doubling is the following: 1. it may be related to low embryonic activity, eventually manifesting as biochemical pregnancy, spontaneous miscarriage, or indolent miscarriage. 2. it may also be hypothyroidism. 3. taking embryonic killing or anti-fertilization drugs. 4. it may also be triggered not only by maternal factors, such as the patient taking drugs during pregnancy that affect the development of the fetus. The actual hcg is not doubled. 5, the pregnant woman is not in a good mood during pregnancy, always throwing tantrums, mental stress, low immunity and other causes. 6, chromosomal abnormalities and other conditions can also lead to hcg not doubled, it is recommended that patients need to go to the hospital for reasonable examination to determine the cause of the disease.