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. The research, published in Nature on April 8, provides new insights into cell types and mechanisms linked to pregnancy complications such as preeclampsia, preterm birth, and miscarriage.
The findings are significant because understanding the maternal-fetal interface can help explain how healthy pregnancies develop and why some pregnancies face complications. This could eventually lead to improved ways of identifying or treating risks during pregnancy.
Researchers used advanced single-cell and spatial analysis tools to examine about 200,000 individual cells from uterine and placental tissue. They compared these with nearly one million cells kept in their original positions within the tissue. This approach allowed them to identify different cell types, track their development, and see how they relate to common pregnancy problems.
“This work gives us a much clearer picture of this critical region than ever before,” said Jingjing Li, Ph.D., associate professor at UCSF’s Department of Neurology and senior author of the study. Susan J. Fisher, Ph.D., professor at UCSF’s Department of Obstetrics, Gynecology and Reproductive Sciences and co-leader of the study said: “By examining this tissue cell by cell across pregnancy, we can begin to understand both normal development and what may go wrong.”
One key discovery was a previously unknown maternal cell type located where fetal placental cells first enter the uterus. These cells appear to regulate how deeply placental cells invade uterine tissue—a process essential for establishing blood flow to the fetus—and carry a cannabinoid receptor that responds to cannabis molecules. “Population studies have linked cannabis use during pregnancy to poorer outcomes,” said Cheng Wang, Ph.D., first author of 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 with regulatory regions controlling gene activity related to conditions like preterm birth or preeclampsia. They found that disrupted communication between specific maternal and fetal cells involved in remodeling uterine blood vessels might be central in causing preeclampsia.
With this detailed map now established for healthy pregnancies, researchers plan further studies focusing on complicated pregnancies with hopes of identifying new targets for treatment.
