Maceração fetal e piometra associadas com o uso de anticoncepcionais em cadelas e gatas: revisão de literatura

Abstract

Although studies have advanced regarding the reproductive management of small animals, the use of hormonal therapy as a contraceptive method to prevent heat cycles and pregnancies is still very common. However, its use has been associated with concerning side effects for female health, leading to the development of uterine diseases such as pyometra, as well as fetal maceration when administered during pregnancy. Therefore, this study aimed to conduct a literature review on fetal maceration and pyometra associated with the use of contraceptives in dogs and cats. Fetal maceration is defined as a septic process of partial and complete destruction of the fetus, occurring after its death, retained in the uterus of pregnant animals. The factors for its occurrence are diverse, with notable causes including extravaginal contamination, dystocia, the use of oxytocin, intrauterine infections by specific bacteria, and the use of progestin contraceptives. Pyometra, on the other hand, is a syndrome of inflammatory processes affecting the reproductive tract of dogs and cats, characterized by the accumulation of purulent secretion in the uterine lumen. The factors for its occurrence are diverse, with hormonal exposure to progesterone being notable, such as during the diestrus phase of the estrous cycle, as well as the application of exogenous progesterone-based contraceptives. It is said that the high concentration of progesterone diminishes the action of oxytocins, estrogens, and prostaglandins, thereby reducing uterine and abdominal contractions. Consequently, if these progestins are administered during pregnancy, it can cause fetal distress and death, leading to subsequent fetal maceration. Additionally, progestins cause a reduction in uterine immune defense, they maintain endometrial growth and glandular secretion. These combined effects result in the accumulation of uterine glandular secretions, leading to an inflammatory response, aiding in the development of pyometra. Therefore, it is concluded that the indiscriminate use of contraceptive drugs to delay or suppress heat cycles is associated with various adverse effects after their use. Both conditions presented in this study represent a serious risk to female health, potentially leading to the death of the animal.