SkiptomaincontentAdvertisementSearchallBMCarticlesSearchDownloadPDFResearcharticleOpenAccessPublished:10December2020Monozygoticdichorionic-diamnioticpregnanciesfollowingsinglefrozen-thawedblastocysttransfer:aretrospectivecaseseriesHeLi ORCID:orcid.org/0000-0001-5025-22121 na1,TingtingShen1 na1&XiaoxiSun1,2 BMCPregnancyandChildbirthvolume 20,Article number: 768(2020)Citethisarticle2434AccessesMetricsdetailsAbstractBackgroundTheprimaryaimofthestudyistoreportcasesofmonozygoticdichorionic-diamniotic(DC-DA)pregnanciesaftersinglefrozen-thawedblastocysttransfer.MethodsThisisaretrospectivecaseseries.Allsinglefrozen-thawedblastocysttransfercyclesperformedbetweenJune2013andDecember2018attheShanghaiJiAiGeneticsandIVFInstitute,ObstetricsandGynecologyHospital,FudanUniversity,Shanghai,China,werereviewedretrospectively.Weincludedfrozenembryotransfer(FET)cycleswhichclinicalpregnancywasconfirmedwithmultiplegestationalsacsshowedonultrasonographyataround6to7 weeksofgestation.Wethenconductedanin-depthanalysistofurtherexcludecaseswhichcontainednewbornsofdifferentgendersornaturalFETcycles.ResultsFivethousandfourhundredfifteenfrozen-thawedsingleblastocysttransfercycleswerepreformedbetweenJune2013andDecember2018attheShanghaiJiAiGeneticsandIVFInstitute,ObstetricsandGynecologyHospital,FudanUniversity,Shanghai,China.Ofthese,fourteenwomenunderwentasingleblastocysttransferandthenachievedclinicalpregnancywithanultrasounddiagnosisofmulti-chorionicpregnancy.WithonenaturalcycleFETexcluded,wefinallyincludedthirteensingleblastocysttransfercyclesperformedindown-regulatedcontrolledFETorhormonereplacementFET,inwhichthepossibilityofconcurrentlyspontaneouspregnancywasextremelysmall.Theseincluded13casesrevealthephenomenonofmonozygoticDC-DAtwinningaftersingleblastocysttransfer,whichchallengestheclassicaltheorythatonlymonochorionicpregnancycouldhappenafter3 daysoffertilization.ConclusionThiscaseseriessuggestthatsingleblastocysttransfercouldresultDC-DApregnanciesduringIVFtreatment.PeerReviewreportsBackgroundW