TTTS is a rare, in utero condition that occurs only in monochorionic twins (identical twins who share the same placenta). Attached to the inside of the uterus ...SkiptoMainContentRelatedSpecialistsUraniaMagriplesMDObstetrics,Gynecology&ReproductiveSciences,Maternal-FetalMedicineMertOzanBahtiyarMDMaternal-FetalMedicine,Obstetrics,Gynecology&ReproductiveSciencesMichaelDiLunaMDNeurosurgeryMoreRelatedSpecialistsPrintShareDownloadOverviewThevastmajorityofpregnanciesunfoldinanormalandhealthyway,butoccasionallythereareproblemsthatrequirehighlyspecializedtreatment.Thishappensmoreoftentowomenwithamultiplepregnancy(orgestation)suchastwinsortriplets.Twin-to-twintransfusionsyndrome(TTTS)isonesuchchallengebutYaleMedicinehasuniqueexpertiseintreatingthisproblem.MertOzanBahtiyar,MD,anobstetrician-gynecologistwhospecializesinhigh-riskpregnanciesandismedicaldirectoroftheYaleMedicineFetalCareCenter,istheonlyphysicianinthestatewhoperformsaprocedurecalledlaserfetoscopytocuretwin-to-twintransfusionsyndrome.TTTSisarare,inuteroconditionthatoccursonlyinmonochorionictwins(identicaltwinswhosharethesameplacenta).Attachedtotheinsideoftheuterusduringpregnancyandconnectedtothefetusbytheumbilicalcord,theplacentadeliversnutrientsandoxygenfromthemother’sbloodtothedevelopingbabies.Withtwin-to-twintransfusionsyndrome,whichoccursin10to15percentofmonochorionictwinpregnancies,thereisanimbalanceinbloodflowduetoplacentalvesselconnections.Onetwin(calledthe“donor”twin)givestoomuchbloodtothe“recipient”twin.Theextrabloodcausestherecipient’skidneystoproducemoreurine,whichcreatesalargebladder.Thiscanleadtotoomuchamnioticfluid(polyhydramnios),prenatalheartfailureorexcessiveswelling(hydrops). Meanwhile,thedonortwindoesn’thaveanyorenoughamnioticfluid.Amnioticfluidisessentialforababy’sdevelopment,buttoomuchortoolittleofitcancauseseriouspregnancycomplications.Twin-to-twintransfusionsyndromeisaprogressivecondition,meaningitgetsworseifnottreatedappropriately.Itusuallydevelopsbetweenweeks16and26ofpregnancyandcanbeeasily