Spontaneous septostomy of the dividing amniotic membrane in diamniotic pregnancies – literature review and case report

Introduction. Monochorionic diamniotic twin pregnancies represent a rare event associated with an extremely rare com­pli­ca­tion of the spontaneous rupture of the di­vi­ding mem­brane between the amniotic sacs. Once this rup­ture ap­pears, the pregnancy becomes functionally a mo­no­am­nio­tic pregnancy, with a high risk of developing umbilical cord entanglement (up to 50%) and a supplementary rise in the perinatal mortality (up to 70%). Materials and method. This literature review included 10 highly selected cases of spontaneous septostomy – respectively, patients with diamniotic pregnancy who didn’t have any invasive procedures, included between 2012 and 2024. Results. In 80% of the identified cases, the diagnosis was established an­te­na­tally, during the ultrasound examination from the se­cond trimester, between 24 and 28 weeks of gestation. One of the most important and severe complications is re­pre­sen­ted by the umbilical cord entanglement (60%). The age of gestation at the moment of delivery varied between 24 and 37 weeks, with the majority being over 32 weeks. The chosen method of delivery, in the majority of cases, was by caesarean section. There are established risk factors for the eventuality of a septostomy; also, the ultrasound elements that can facilitate the diagnostic, maintaining the necessity of an anatomopathological confirmation. Conclusions. Du­ring the monochorionic diamniotic pregnancy, the spon­ta­neous rupture of the dividing membrane is an extremely rare event, with a high difficulty of diagnosis antenatally. Once the diagnostic was established, the pregnancy should be­ne­fit from a management similar to that of mo­no­cho­rio­nic pregnancy.