Imaging reveals unexpected contractions in the human placenta

Blood circulation in the human placenta is critical for fetal development. A technique called magnetic resonance imaging (MRI) is increasingly used to study fetal growth and development. In the new study, Gowland and colleagues used MRI to shed light on the movement and oxygenation of blood in the human placenta.

The researchers observed relatively uniform, high oxygenation levels across the whole placenta, and a decrease in the velocity of blood flow as it enters the placenta. These findings suggest that oxygen is delivered efficiently from the mother to the fetus. The researchers also observed rapid draining from veins in the placenta, a feature that is crucial for proper circulation but has largely been neglected in past studies.

Moreover, they discovered a new physiological phenomenon, named the utero-placental pump, by which the placenta and underlying uterine wall contract independently of the rest of the uterus. Such contractions facilitate better blood flow through the placenta and the fetus.

Finally, the researchers characterized altered patterns of blood movement associated with pre-eclamptic pregnancies, which are characterized by the onset of high blood pressure and often a significant amount of protein in the urine, increasing the risk for poor outcomes for both the mother and the baby. According to the authors, their results can be used to improve placental models and to optimize MRI protocols to provide more specific information about placental abnormalities.