Placenta accreta spectrum (PAS) is now recognized as an abnormal uterine healing disorder rather than a consequence of excessive trophoblastic invasion. Contemporary biologic evidence demonstrates that PAS originates from a persistent uterine scar characterized by disrupted collagen architecture, impaired decidualization, and altered extracellular matrix organization at the site of previous uterine injury.
Normal implantation depends on an organized decidual matrix that provides mechanical resistance and spatial regulation of trophoblastic invasion. In PAS, this regulation is lost. Disorganized collagen types I and III, indistinct decidual-myometrial borders, and reduced scar resistance create a permissive environment for abnormal placental adherence rather than physiological separation. These findings establish a direct mechanistic link between extracellular matrix abnormality and PAS.
This biologic framework has direct implications for surgical management. Uterine-conserving strategies for PAS are often grouped together. However, they differ fundamentally in their biologic consequences. Conservative approaches that leave the placenta in situ preserve the damaged myometrium and the abnormal collagen matrix. Although such strategies may reduce immediate hemorrhagic risk, they maintain the same pathologic substrate responsible for the index PAS. Delayed morbidity and recurrence in subsequent pregnancies have been reported after the placenta is left in situ, supporting the concept that the underlying defect remains uncorrected.
In contrast, conservative surgical approaches that include complete resection of the scarred myometrium aim to eliminate the biologic origin of PAS. The surgical principles of 1-step conservative surgery closely align with PAS pathophysiology. By excising compromised uterine tissue and reconstructing the uterus with healthy, well-vascularized myometrium, these techniques seek to restore normal anatomy and extracellular matrix organization rather than merely preserving the uterus as an organ. In this context, uterine conservation becomes functional and potentially preventive, as demonstrated by large published series without recurrence.
A parallel concept is observed in cesarean scar pregnancy, which shares the same scar-based etiology as PAS. Medical or nonsurgical treatments that terminate the pregnancy without excising the scar leave the underlying collagen disorganization and myometrial defect intact. Recurrence has been documented when the damaged myometrium is not surgically corrected, reinforcing the importance of scar resection in preventing repeat abnormal implantation. Therefore, cesarean scar pregnancy and PAS represent different temporal manifestations of the same pathologic process.
From both biologic and surgical perspectives, the conservative management of PAS should be clearly distinguished between approaches that leave the damaged myometrium in place and those that resect and reconstruct it, directly addressing the underlying extracellular matrix disruption.
The authors report no conflict of interest.
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