From a Western medical perspective, there are many possible causes of tendency to miscarriage including abnormal chromosomal embryos or factors such as the mother having high fever or kidney disease.
Threatened miscarriage has been treated with Chinese medicine for centuries and is broadly divided into two causative types, one due to Kidney deficiency and the other Spleen deficiency. The Kidneys are regarded as the main system being responsible for controlling reproductive power and treatment aimed to bolstering Kidney energy is given in the first trimester. Miscarriage that occurs during the second trimester is often treated by fortifying the Spleen energy. Traditional theory advocates that the Spleen has the function of drawing up the energy to hold the body in place. Hence if the Spleen energy becomes weak, symptoms such as prolapse, hernia and hemorrhoids could result. In addition, the Spleen energy needs to be strong to hold the baby in place and prevent miscarriage.