dichorionic diamniotic (DCDA) twins – each has their own separate placenta with its own separate inner membrane (amnion) and outer membrane (chorion) ...SkiptomaincontentHomePregnancyYourpregnancycareBacktoYourpregnancycareAntenatalcarewithtwinsWhenyou'reexpectingtwinsortriplets,it'simportantthatyouattendallyourappointmentsbecauseoftheincreasedriskswiththistypeofpregnancy.Yourantenatalteamshouldbeexperiencedincaringforwomenhavingtwinsortriplets.Check-upsandscansinatwinpregnancyThenumberoftestsandscansyou'llbeofferedwilldependonthetypeoftwinsortripletsyou'rehaving.Womenwithmultiplepregnanciesshouldbeofferedanultrasoundscanataround11to14weeks.It'simportanttoattendthisappointment.Thisisthebesttimetofindoutwhattypeofplacentaandmembranesyourtwinshave(chorionicity)andcheckyourdates.YoucanalsohaveanuchaltranslucencytestforDown'ssyndromedoneatthesametimeifyouwish.FindoutmoreaboutscreeningforDown'ssyndromeYou'llalsobeofferedascan,calledananomalyscan,around18to20weeks6daystocheckthatyourbabiesaredevelopingnormally.DifferenttypesoftwinsFormedicalpurposes,thereare3typesoftwins.Theseapplytotripletstoo,althoughatripletpregnancywillbemorecomplexthanatwinone.The3typesare:dichorionicdiamniotic(DCDA)twins–eachhastheirownseparateplacentawithitsownseparateinnermembrane(amnion)andoutermembrane(chorion)monochorionicdiamniotic(MCDA)twins–shareasingleplacentawithasingleoutermembraneand2innermembranesmonochorionicmonoamniotic(MCMA)twins–shareboththeinnerandoutermembranesAllnon-identicaltwinsareDCDA,andathirdofidenticaltwinsareDCDA.Theothertwo-thirdsofidenticaltwinsareMCDA,andjust1in100identicaltwinsareMCMA.Thepercentagesofidenticalandnon-identicaltwinsbornintheUKarenotroutinelyrecorded,butaccordingtotheMultipleBirthsFoundationaboutathirdoftwinsareidentical.WhatextracaremayIneed?IfyourbabiesareMCDA,youcanexpectmorescansandmonitoring,asthistypeoftwinshasthehighestriskoftwin-twintransfusionsyndrome(TTTS),whichis anabnormalityoftheplacenta.Youmaybereferredtoaregionalcentreforfoetalmedicinetobes