Management of Borderline Twin-to-Twin Transfusion Syndrome With Fetoscopic Laser Therapy in a Monochorionic Diamniotic Twin Pregnancy.

Monochorionic diamniotic (MCDA) twin pregnancies are associated with a high risk of complications due to shared placental vascular anastomoses, which predispose fetuses to twin-to-twin transfusion syndrome (TTTS) and twin anemia-polycythemia sequence (TAPS). Early recognition of subtle hemodynamic alterations is essential, as borderline forms of these conditions may progress rapidly and jeopardize fetal well-being. This case report presents a 30-year-old gravida 2, para 1, with an MCDA twin pregnancy complicated by borderline TTTS and TAPS, who underwent fetoscopic laser therapy despite not meeting strict Quintero criteria. Ultrasound assessment at 22 weeks' gestation revealed significant polyhydramnios and early Doppler abnormalities in the recipient twin, accompanied by mildly altered Doppler indices and borderline amniotic fluid reduction in the donor twin. Although diagnostic thresholds for classic Stage I TTTS or definitive TAPS were not fully met, the combination of symptomatic polyhydramnios, Doppler disturbances, and the patient's high-risk maternal background, including chronic hypertension and a previous pregnancy complicated by severe preeclampsia and intrauterine growth restriction, prompted referral to a specialized fetal therapy center. Fetoscopic laser coagulation and amnioreduction were performed, resulting in rapid normalization of Doppler parameters and amniotic fluid volumes. Weekly post-procedural surveillance demonstrated stable fetal growth and restored hemodynamic balance. Cesarean delivery at 36 weeks' gestation resulted in two healthy male neonates with favorable Apgar scores and an uncomplicated postpartum course. This case underscores the importance of individualized management and timely intervention in MCDA twin gestations, even when classical staging systems are not fully satisfied. Early detection of evolving hemodynamic compromise, strict adherence to standardized surveillance protocols, and multidisciplinary collaboration are crucial for optimizing maternal and perinatal outcomes in borderline TTTS and TAPS.