Herniation of Ovular Membranes through a Myometrial Defect following Fetoscopic Laser Therapy for Twin-to-Twin Transfusion Syndrome: An Underrecognized Maternal Complication.

INTRODUCTION: Fetoscopy is a minimally invasive technique widely used for the treatment of twin-to-twin transfusion syndrome (TTTS), offering significant perinatal benefits. However, maternal complications of fetoscopy are underreported and incompletely characterized.

CASE PRESENTATION: We present the case of a 19-year-old primigravida with a monochorionic diamniotic pregnancy, diagnosed with Quintero stage II TTTS at 18 weeks of gestation, managed with fetoscopy and laser ablation. The clinical course remained stable until 30+3 weeks, 12 weeks after the fetoscopic procedure, when fetal demise of the donor twin and preterm labor were documented, prompting cesarean delivery. During surgery, a 5-mm myometrial defect was identified in the anterior-left lateral uterine wall, with herniation of ovular membranes through the defect at the site of the previous trocar insertion. This long interval between fetoscopy and detection of the defect is notably unusual.

CONCLUSION: Herniation of ovular membranes through a myometrial defect is an uncommon and often asymptomatic complication following fetoscopy, which can be diagnosed incidentally during cesarean delivery, as in our case. The identification of this defect 12 weeks post-procedure highlights the importance of prolonged surveillance. Therefore, a thorough ultrasound assessment, including the fetus, amniotic fluid, and careful evaluation of the uterine wall for potential defects, should be considered a routine part of post-fetoscopy care.