Background:　Health　care　is　experiencing　new　opportunities　in　the　emerging　digital　landscape.　The　metaverse,　a　shared　virtual　space,　integrates　technologiessuch　as　augmented　reality,　virtual　reality,　blockchain,　and　artificial　intelligence.　It　allows　users　to　interact　with　immersive　digital　worlds,　connect　with　others,　and　explore　unknowns.　Whilethe　metaverse　is　gaining　traction　across　various　medical　disciplines,　its　application　in　thyroid　diseases　remains　unexplored.　Subclinical　hypothyroidism　(SCH)　is　the　most　common　thyroid　disorder　during　pregnancy　and　is　frequently　associated　with　adverse　pregnancy　outcomes.　Objective:　This　study　aims　to　evaluate　the　safety　and　effectiveness　of　a　metaverse　platform　in　managing　SCH　during　pregnancy.　Methods:　A　randomized　controlled　trial　was　conducted　at　Fujian　Provincial　Hospital,　China,　fromJuly　2022　to　December　2023.　A　total　of　60　pregnant　women　diagnosed　with　SCH　were　randomly　assigned　into　two　groups:　the　standard　group　(n=30)　and　the　metaversegroup　(n=30).　Both　groups　received　levothyroxinesodium　tablets.　Additionally,　participants　in　the　metaversegroup　had　access　to　the　metaverse　virtual　medical　consultations　and　metaverse-based　medical　games.　The　primary　outcomeswere　adverse　maternal　and　offspring　outcomes,　and　the　secondary　outcomes　included　the　neurobehavioral　development　of　offspring　and　maternal　psychological　assessments.　Results:　Of　the　30　participants　in　each　group,　adverse　maternal　outcomes　were　observed　in　43%　(n=13)　of　the　standard　group　and　37%　(n=11)　of　the　metaverse　group　(P=.60).　The　incidence　of　adverse　offspring　outcomes　was　33%　(n=10)　in　the　standard　group,　compared　to　7%　(n=2)　in　the　metaverse　group　(P=.01).　The　Gesell　Development　Scale　did　not　show　significant　differences　between　the　two　groups.　Notably,　the　metaverse　group　demonstrated　significantly　improved　scores　on　the　Self-Rating　Depression　Scale　and　the　Self-Rating　Anxiety　Scale　scores　compared　to　the　standard　group　(P＜.001　and　P=.001,　respectively).　Conclusions:　The　use　of　metaverse　technology　significantly　reduced　the　incidence　of　adverse　offspring　outcomes　and　positively　impacted　maternal　mental　health.　Maternal　adverse　outcomes　and　offspring　neurobehavioral　development　were　comparable　between　the　two　groups.　Trial　Registration:　ChineseClinicalTrialRegistry　ChiCTR2300076803;https://www.chictr.org.cn/showproj.html?proj=205905