Pseudopregnancy in cats is mainly related to the corpus luteum formed in the ovaries after the cat is in heat and ovulates. When a cat's body is abnormal, the corpus luteum exists in the ovary for a long time and continuously secretes progesterone and estrogen, keeping the two hormones in the cat's body at levels comparable to those during pregnancy. Progesterone is responsible for maintaining pregnancy and causing major changes in pregnancy. Factors, so the cat will have the same symptoms as pregnancy at this time, which is a false pregnancy.