WS12-06Doppler evaluation of IUGR fetuses

Intrauterine growth restriction (IUGR) is now defined as a condition in which the fetus does not reach the optimal condition of his growth. In this situation the birthweight can be reduced below the 10th percentile or can be superior to that threshold especially when the restriction took first place in late part of the pregnancy. Therefore it is possible to identify two groups of IUGR according to the intrauterine observation and the birthweight assessment: SGA and AGA IUGR. The most important complication of IUGR is represented by the hypoxaemia caused by placental vasculopathy. Hypoxaemia is present in about 30% of IUGR fetuses with not significant difference between SGA and AGA IUGR cases, and is the major cause of the poor perinatal outcome. After recognition of the growth restriction it is necessary to apply second level tests in order to assess the presence or absence of hypoxaemia. When hypoxaemia is present the first mechanism of fetal adaptation is represented by the redistribution of the circulation. This phenomenon is easily observable by using Doppler technology. When applying the same technique on the umbilical arteries it is possible to detect an increase in the peripheral resistance proportional to the obliteration of the placental vascular bed that is the cause of the fetal hypoxaemia. By using the information offered by Doppler study on fetal and umbilical vessels it is therefore possible to optimize the clinical management of the IUGR fetuses.