UC San Francisco scientists announced on April 9 that they have mapped the biological connection between pregnant women and their developing babies in unprecedented detail, revealing new cell types and potential links to pregnancy complications such as preeclampsia, preterm birth, and miscarriage.
The research provides a clearer understanding of how the maternal-fetal interface functions during pregnancy. This knowledge may help explain why some pregnancies develop complications, potentially leading to better prevention or treatment strategies in the future.
Using advanced single-cell and spatial analysis tools, the team examined about 200,000 individual cells and compared them with nearly one million cells within uterine and placental tissue. This allowed researchers to identify various cell types, track their development over time, and observe how they relate to common pregnancy issues. “This work gives us a much clearer picture of this critical region than ever before,” said Jingjing Li, Ph.D., associate professor in UCSF’s Department of Neurology and senior author of the study published in Nature on April 8.
The maternal-fetal interface is a temporary structure made up of uterine and placental cells that forms shortly after fertilization. It plays an essential role throughout pregnancy by supporting fetal growth while maintaining maternal health. Its complexity has made it difficult for scientists to fully understand how healthy pregnancies progress or why certain complications arise. “By examining this tissue cell by cell across pregnancy, we can begin to understand both normal development and what may go wrong,” said Susan J. Fisher, Ph.D., professor at UCSF’s Department of Obstetrics, Gynecology and Reproductive Sciences.
One significant finding was the discovery of a previously unknown type of maternal cell located where fetal placental cells first enter the uterus. These cells appear to control how deeply placental cells invade uterine tissue—a process necessary for establishing blood flow to the fetus—and carry cannabinoid receptors that can be affected by cannabis exposure during pregnancy. “Population studies have linked cannabis use during pregnancy to poorer outcomes,” said Cheng Wang, Ph.D., first author on the study. “This cell type may help explain the biological basis of that association.”
The team also integrated genetic data from more than 10,000 patients into their atlas in order to pinpoint which regulatory regions are associated with risks for conditions like preterm birth or preeclampsia. They found evidence suggesting disrupted communication between certain maternal and fetal cells could play a key role in these disorders.
With this detailed map now established for healthy pregnancies, researchers plan next to investigate complicated pregnancies as they search for possible targets for treatment.
