Researchers create single-cell atlas of the placenta during full-term labor

An atlas revealing the activity of individual placental cells during childbirth offers insight into what happens at the maternal-fetal interface during full-term labor, according to a new study. The work, led by researchers at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), is published in the latest issue of Scientific translational medicine.

The atlas provides a single-cell analysis of the human placenta and its surrounding membranes and is the first to use this method to understand the communication that occurs between maternal and fetal cells during the labor process. Studying these processes facilitates the understanding of typical full-term labor and delivery, as well as preterm labor and delivery, which occurs before 37 weeks of gestation and is a leading cause of infant death and long-term disability.

The study team created the placental atlas using single-cell RNA sequencing (also called single-cell transcriptomics), which examines the activity and signaling patterns of individual cells. The atlas, based on samples from 42 full-term pregnancies, describes changes in gene expression patterns among different cell types in the placenta and its surrounding membranes, which include both maternal and fetal cells.

Researchers found that the cells most affected by labor were in the chorioamniotic membranes, which surround the fetus and rupture as part of the labor and delivery process. They also found that fetal stromal and maternal decidual cells were particularly active in generating inflammatory signals. These results are consistent with previous research showing that inflammation (not related to infection) is important for maintaining work.

The study is also a proof of concept that placental biomarkers present in maternal blood can be used to identify pregnancies at risk of preterm birth. Researchers used the atlas to classify specific cellular signatures of labor detectable in maternal blood samples from term and preterm pregnancies. However, further validation is needed in larger studies.

This work was conducted by the Pregnancy Research Branch of the NICHD and led by Roberto Romero, MD, D.Med.Sci., NICHD; Nardhy Gomez-Lopez, Ph.D., University of Washington School of Medicine; and Roger Pique-Regi, Ph.D., Wayne State University.