The natural history of twin–twin transfusion syndrome stratified by Quintero stage*

Objective: To describe the natural history of expectantly managed twin–twin transfusion syndrome (TTTS) specific to disease stage. Methods: This was a retrospective study of monochorionic diamniotic pregnancies diagnosed with TTTS and delivered between 1997 and 2013. Staging was based on Quintero’s criteria, with sonogram images reviewed to confirm findings specific to stage. Progression and outcomes were evaluated in pregnancies that did not receive any form of therapy. Results: Thirty-eight pregnancies were diagnosed with TTTS and delivered at our institution, representing 1.6 per 10 000 births. Twenty were expectantly managed, of which 50% were stage I at presentation. Progression occurred in 45% of pregnancies, including 50% initially diagnosed with stage I TTTS. Seventy percent of pregnancies experienced survival of at least one twin, with no stillbirths or neonatal deaths if TTTS resolved. Pregnancies in which TTTS was either stable or improved had higher overall survival, compared with pregnancies that experienced progression, 86% versus 22%, p < 0.001, as well as more frequent survival of one or both twins, 91% versus 44%, p = 0.02. Conclusions: Among expectantly managed pregnancies with TTTS, most had early disease at diagnosis. Although 45% of cases progressed, which conferred poor prognosis, the majority experienced disease stabilization or improvement.