New research from GIFT-Surg and the University of South Australia has shown that magnetic resonance imaging (MRI) can be used to gather detailed information about placental development during pregnancy; the findings are important as most information on human placental biology has previously been obtained by studying placental tissue after delivery.
The study published in the journal Placenta can pave the way to better understanding the structure and function of the placenta, which will facilitate the development of both preventative and therapeutic interventions targeting abnormalities of placental development and function such as placental insufficiency and fetal growth restriction (FGR).
The international research team used MRI to look in detail at placental development of pregnant ewes – animals that serve as a useful model for human placental development – during pregnancy.
Through this, the researchers were able to classify placentomes (fetal and maternal tissue involved in the formation of the placenta) based on their shape and size, and measure information about the changes to the internal structure relating to blood perfusion and oxygenation between two gestational ages.
The results showed consistent patterns with known gestational age changes in sheep placental development, as supported by post-delivery gold standard placentome examination.
Figure 1: Example of MR images illustrating morphological classification of placentomes in a single sheep at 109–111 days gestational age
Dr Dimitra Flouri, Research Associate in Computational Medical Imaging at King’s College London and the lead researcher on the study said: “We reported baseline measurements of techniques common in placental MRI measures in uncomplicated pregnancy. Our research shows that MRI can be used to look in detail at the development of the placenta during pregnancy.”
Professor Anna David, Professor of Obstetrics and Maternal Fetal Medicine at UCL and one of the authors of the research said: “This study is the first to use novel MR imaging to better understand how placental structure is related to function. It will help scientists and clinicians develop new treatments to target the placenta so as to improve outcomes for babies.”
For ethical reasons, validating measurements of placental function in human subjects is not possible, necessitating the use of an appropriate animal model. Although no animal model truly represents human pregnancy, sheep have been extensively used to study maternal-fetal interactions as they represent a model of relevant dimensions to human pregnancy and because of their amenability to surgical intervention.
The research team is now extending the work to validate specific markers of the fetal oxygenation level measured on MRI based on their earlier results in human pregnancy. Establishing robust validation of these results with placenta tissue properties will help support the translation of advanced placental MRI measurements into the clinical setting.