Birth mode is associated with layer-specific mechanical changes in fetal membranes

Area of Science:

• Biomedical Engineering
• Materials Science
• Obstetrics

Background:

• Fetal membrane rupture is crucial for childbirth, but preterm rupture poses severe neonatal risks.
• Understanding the mechanical properties of fetal membranes is key to identifying factors contributing to rupture.

Purpose of the Study:

• To determine the mechanical properties and structural changes in term fetal membranes.
• To investigate the role of the intermediate connective tissue layer in membrane stability and rupture.

Main Methods:

• A biophysical multiscale approach was used, including atomic force microscopy, shear rheology, magnetic resonance elastography (MRE), and optical microscopy.
• Term fetal membranes from spontaneous vaginal deliveries were compared to pre-labor membranes from cesarean sections.

Main Results:

• Spontaneously delivered membranes were significantly softer (1.9 kPa vs. 4.7 kPa) and showed increased water diffusion compared to controls.
• The intermediate connective tissue layer exhibited less ordered fiber alignment and a looser structure (lower fiber area fraction).

Conclusions:

• Layer-specific changes in structure and viscoelasticity highlight the intermediate connective tissue's role in membrane stability.
• Mechanics-based screening methods may help assess the risk of preterm rupture, potentially reducing neonatal morbidity.