Mary Spring: The impact of fetal sex on placental vascular structure and function in fetal growth restriction.

<p dir="ltr">The placenta facilitates maternal–fetal oxygen and nutrient exchange, supporting fetal growth. Placental dysfunction is a leading cause of fetal growth restriction (FGR), where babies are born dangerously small. Sex-specific differences in placental function exist; males prioritise fetal over placental growth, increasing vulnerability under stress and increasing their FGR incidence. However, sex-specific differences in placental anatomy and function in FGR remain poorly defined. Using computational models, we investigated how sex-specific placental vascular anatomy influences blood flow. Models parameterised from the largest vessels of normal (female n=20, male n=22) and FGR (female n=3, male n=6) placentae predicted that normal male placentae required lower pressures to achieve equivalent blood flow compared with females, while male FGR placentae exhibited 2.6–3× higher vascular resistance than female or controls. This suggests increased pressure is needed to maintain adequate placental blood flow, indicating structural differences in male FGR placentae may contribute to their increased vulnerability. </p>