Fetoplacental complex parameters’ changes during repeated increase of the blood volume in female rabbits

One of the mandatory stages of introducing new drugs into obstetric practice is preclinical trials, the purpose of which is to study the effect of drugs on the development of fetuses and placentas. When conducting experimental studies, the main group of animals receiving the drug is compared with the control group of animals that do not receive drugs. At the same time, the volume of the test drug itself can significantly change the blood volume (BV) of an experimental animal, especially a small one, and such administration repeated repeatedly over several days can accumulate this effect, having an adverse effect on the functional state of the fetus. A model of chronic placental insufficiency created on the 18th day of pregnancy in female rabbits by ligating 1/3 of the preplacental vessels in one uterine horn was used to study the effect on the development of the brain and placenta of normally developed and retarded fetuses of multiple daily (1928 days of pregnancy) infusions of saline solution to females in a volume of 6% of the animals BV and comparable to the volume of medications used in the treatment of placental insufficiency in clinical practice (main group of rabbits). It was found that repeated daily administration of saline solution to a female rabbit in the second half of pregnancy, which is about 6% of the BV, causes a violation of the functional state of her normally developed and, to an even greater extent, retarded fetuses. This is manifested by a 1.4-fold reduced survival rate of fetuses in the intact horn of the uterus and a more pronounced violation of brain metabolism in fetuses of the intact and experimental horns compared to those of the control group of females.