Selective Fetal Growth Restriction in Monochorionic Twins: Updates and New Directions.

Selective fetal growth restriction (sFGR) in monochorionic twin pregnancies is a major contributor to perinatal morbidity and mortality with unique pathophysiological mechanisms and management challenges. sFGR is defined by significant intertwin discordance in estimated fetal weight and abnormal Doppler findings, employing the Gratacós classification (types I, II, and III) for risk stratification and management. Epidemiological data indicate sFGR affects 10% to 26% of monochorionic twins, with early-onset cases associated with the highest risk of adverse outcomes. Surveillance strategies include frequent ultrasound and Doppler assessment, and management is tailored to sFGR type, gestational age, and fetal condition. Expectant management is favored for type I sFGR, while type II and III may require fetal intervention, including fetoscopic laser photocoagulation or selective reduction, though practice variation remains substantial. Recent meta-analyses highlight the importance of Doppler progression, gestational age at diagnosis, and ductus venosus findings as predictors of fetal demise. Advances in imaging, biomarkers, and intervention techniques are shaping future practice, but randomized trials are needed to clarify optimal strategies. Controversies persist regarding timing of intervention, ethical considerations, and outcome prediction. In conclusion, individualized, multidisciplinary management is essential, and ongoing research should focus on refining diagnostic criteria, improving neurodevelopmental outcomes, and developing evidence-based guidelines.