Monitoring fetal well-being in labor in late fetal growth restriction.

Abstract

Late-onset fetal growth restriction (FGR) accounts for approximately 70-80% of all cases of FGR secondary to uteroplacental insufficiency. It is associated with an increased incidence of adverse antepartum and perinatal events, which in most instances result from hypoxic insults either present at the onset of labor or supervening during labor as a result of uterine contractions. Labor represents a stressful event for the fetoplacental unit being uterine contractions associated with an up-to 60% reduction of the uteroplacental perfusion. Intrapartum fetal heart rate monitoring by means of cardiotocography (CTG) currently represents the mainstay for the identification of fetal hypoxia during labor and is recommended for the fetal surveillance during labor in the case of FGR or other conditions associated with an increased risk of intrapartum hypoxia. In this review we discuss the potential implications of an impaired placental function on the intrapartum adaptation to the hypoxic stress and the role of the CTG and alternative techniques for the intrapartum monitoring of the fetal wellbeing in the context of FGR secondary to uteroplacental insufficiency.