FRIDAY, May 29, 2020 (HealthDay News) -- MRI imaging has uncovered key differences in blood flow to the placenta in pregnant women who are healthy and those with preeclampsia.
That could help explain why babies born to mothers with preeclampsia -- dangerously high blood pressure during pregnancy -- are often smaller and premature, according to researchers at the University of Nottingham in the United Kingdom.
The MRI scans also revealed an unexpected finding: The life sustaining organ contracts to help preserve blood flow, scientists say.
The placenta is key to the movement of nutrition and oxygen from mother to fetus. An improperly functioning placenta can lead to preeclampsia.
In this new study, the Nottingham researchers used MRI to observe placental blood flow in 34 women with healthy pregnancies and 13 women with preeclampsia.
"We found that in healthy pregnancies the blood flows very slowly. This seems odd at first but our other measurements suggest that this is a way in which the placenta can function efficiently," said study leader Neele Dellschaft, a research fellow in Nottingham's School of Physics and Astronomy.
Normal patterns of blood flow and oxygenation were more variable in preeclampsia, she added.
The researchers also identified a "completely new phenomenon," which they have dubbed the "uteroplacental pump."
It's a contraction of the placenta and part of the uterine wall to which it is attached -- different from the well-known Braxton-Hicks contractions that often precede labor. Dellschaft said these newly discovered contractions might function to prevent blood stagnation in parts of the placenta.
Study co-author Penny Gowland noted that there are no clinical tools right now to assess placental function directly.
"All we can do is assess the size and growth of the baby and blood flow in the umbilical cord using ultrasound," Gowland said in a university news release.
"This research demonstrates that MRI is hugely effective in providing detailed information of exactly what is happening between the baby and the mother and what is changed in a preeclampsia pregnancy," Gowland said. "It's also hugely exciting to have discovered a brand new physical phenomenon that takes place during pregnancy. We hope in the future this knowledge can be built upon by clinicians to better diagnose and manage conditions like preeclampsia."
Gowland is a professor at Nottingham's Sir Peter Mansfield Imaging Center.
The study was published online May 28 in the journal PLOS Biology.
The March of Dimes has more on preeclampsia.