The importance of Doppler evaluation in predicting fetal growth restriction and adverse neonatal outcomes in low-risk pregnant population

The placenta, often described as the lifeline between mother and fetus, is a complex multitasking organ essential for sustaining pregnancy and ensuring healthy fetal development [1]. As the principal interface between the mother and the fetus, it plays a critical role in the transfer of oxygen, nutrients, and waste products while also producing hormones crucial for maintaining pregnancy [2]. This intricate organ not only supports fetal growth but also modulates maternal physiological adaptations to pregnancy. Adequate uterine vascularization is essential to allow a correct placentation invasion and development during the first stages of pregnancy and to provide the necessary amount of blood supply to the placenta and then the fetus for its growth. Despite its critical role, placental insufficiency - characterized by impaired placental function and inadequate nutrient and oxygen supply - can lead to significant adverse outcomes, including miscarriage, stillbirth, fetal growth restriction, and hypoxia at birth, with increased risks of perinatal morbidity and mortality [3]. In fact, pathologies such as pre-eclampsia and fetal growth impairment are associated with inadequate quality and quantity of the maternal vascular response to placentation [4,5]. In both conditions, there are characteristic pathological findings in the placental bed. Understanding the mechanisms behind placental insufficiency and its impact on fetal growth is therefore crucial for developing effective diagnostic and therapeutic strategies to improve pregnancy outcomes. In this context, during my PhD course, I deepened into fetal and maternal vascular adaptation to pregnancy in normal and pathological conditions using Doppler ultrasound evaluation of various compartments. The participation of our Institution in a multicentric randomized controlled trial about the best ultrasound screening program for the detection of small for gestational age neonates allowed us to propose a novel protocol for the surveillance of fetuses at higher risk of impaired growth in the third trimester of pregnancy. At the same time, an original prospective observational study on cardiovascular maternal adaptation to pregnancy in a selected low-risk population of pregnant women at term conducted in our Institution shed light on the importance of maternal cardiac performance at the end of pregnancy to predict adverse obstetrical outcomes at delivery. In this final work, I proudly present the results of these two original studies which have in common the pathophysiology of vascular maladaptation to pregnancy from both fetal and maternal points of view, discussing the implications of these insights for addressing fetal growth restriction and adverse obstetrical outcomes at birth.