Transparent discharge from female cats may be caused by estrus or after mating. If there are no other symptoms or abnormalities, there is no need to worry too much. If the secretion is yellow or light yellow, it may be pyometra, and you need to go to a pet hospital for examination and treatment. In serious cases, the uterus may need to be removed. If a female cat does not mate and give birth for many years, she will easily develop pyometra. Therefore, if you do not plan to let the female cat give birth, it is best to undergo sterilization surgery in advance.