The morphogenesis of fetal blood vessels in placental insufficiency in pregnant women

The morphogenesis of additional smooth muscle structures of the visceral arteries of the fetus and placenta in its hypoplasia was examined to identify the features of their structure, localization, and values for circulation. Histological, histochemical, and morphometric studies were used to investigate the fragments of ventricles, lung, liver, kidney, brain, placenta, and umbilical cord from 34 fetuses that had died from chronic placental insufficiency at 28–29 weeks’ gestation. A comparison group included 10 cases in the same period, fetal and placental masses, and gestational age. The development of a set of smooth muscle structures of the inner coat of vessels is shown to be stimulated in the arterial bed of the fetus and placenta in placental hypoplasia in circumstances where the terminal villi and lumen of their capillaries are reduced. The regulatory adaptive elements involved in arterial luminal changes are divided into polypoid cushions, sphincters, and intimal muscles; they promote the rational distribution of blood streams in the organs and placenta, by reducing trophic and oxygen deprivation in the fetus