INTRODUCTION: While fetoscopic laser coagulation (FLC) has been shown to improve outcomes in twin-twin transfusion syndrome (TTTS) at higher stages, the management of stage I TTTS remains controversial. We sought to examine the cost-effectiveness and outcomes associated with FLC versus expectant management and the resultant effects on rates of single intrauterine fetal demise (IUFD), dual IUFD, delivery <32weeks, and neurocognitive disability. METHODS: A cost-effectiveness model using TreeAge software was designed to compare outcomes in monochorionic diamniotic (MCDA) pregnancies complicated by stage I TTTS in twins managed with FLC versus expectant management using a theoretical cohort of 100,000 women. Probabilities were derived from the literature, and a cost-effectiveness threshold was set at $100,000 per QALY. RESULTS: When twin pregnancies complicated by stage I TTTS were treated with FLC there were higher rates of single and dual stillbirth, more deliveries <32 weeks, but fewer cases of neurocognitive disability. Additionally, there would be increased costs and lower QALYs making FLC a dominated strategy. In our theoretical cohort, expectant management led to 1811.8 fewer single IUFDs, 2569.9 fewer dual IUFDs, 1133.3 fewer deliveries <32 weeks, 6370.4 more neurodevelopmental disability, and saving $20,134.29 with 1.9 increased QALYs. Sensitivity analysis of probability of IUFD after FLC, demonstrated that below a probability of 29.5%, using FLC becomes the cost effective strategy. CONCLUSION: In MCDA twin pregnancies affected by stage I TTTS, expectant management resulted in improved outcomes, decreased costs, and increased QALYs. Of note, the rate of neurocognitive disability was increased in the expectant management group.