Anatomy of the Fetal Membranes: Insights from Spinning Disk Confocal Microscopy

Abstract

Abstract Purpose The fetal membrane is essential for the maintenance of pregnancy, and its integrity until parturition is critical for both fetal and maternal health. Preterm premature rupture of the membranes (pPROM) is known to be an indicator of preterm birth, but the underlying architectural and mechanical changes that lead to fetal membrane failure are not yet fully understood. The aim of this study was to gain new insights into the anatomy of the fetal membrane and to establish a tissue processing and staining protocol suitable for future prospective cohort studies. Methods In this proof of principle study, fetal membranes were collected from both vaginal delivery and cesarean section. Small membrane sections were then fixed, fluorescently stained for nucleic acids, actin, and collagen, and subsequently imaged in three dimensions using a spinning disk confocal microscope. Results Four fetal membranes of different types were successfully processed and imaged after establishing a suitable protocol. Cellular and nuclear outlines are clearly visible in all cases, especially in the uppermost membrane layer. Focal membrane (micro)fractures could be identified in several samples. Conclusion The presented method proves to be well suited to determine whether and how the occurrence of membrane (micro)fractures and cellular jamming correlates with the timing of membrane rupture and the mode of delivery. In future measurements, this method could possibly be combined with mechanical probing techniques to compare optical and mechanical sample information.