Bioengineering of foetal membrane repair.

Preterm premature rupture of the foetal membranes (früher vorzeitiger Blasensprung) has remained a devastating complication of pregnancy with very high risk of pregnancy loss. Several methods of sealing spontaneously ruptured membranes to stop amniotic fluid leakage and prolong pregnancy have been tested, but no one of them has achieved a clinical breakthrough. Also, needle and foetoscopic puncture of membranes for diagnostic or surgical interventions in the amniotic cavity carry a significant risk of persistent membrane leakage and subsequent rupture - thus limiting the developing field of intrauterine foetal surgery. Efforts are concentrated on taking action before rupture rather than reacting after rupture: one avenue of research concerns prophylactic plugging of foetoscopic access sites in foetal membranes at the time of intervention, thus inhibiting leakage and rupture. Foetal membrane injuries, spontaneous or iatrogenic, constitute extreme challenges to repair: thinness of foetal membrane tissue, difficult localisation and accessibility of the rupture site, the need for injectable sealants, wet gluing conditions and poor wound healing in this tissue all complicate repair. The goal is to achieve immediate and at the same time long-lasting closure of the membrane leak. Here we review approaches to closure of foetal membrane defects with liquid sealants or solid biomaterial scaffolds, with the focus on prophylactic plugging of foetoscopic access sites.