Blood Chimerism in a Dizygotic Dichorionic Pregnancy

Confined Blood Chimerism in Monochorionic Dizygotic Twins Conceived Spontaneously

“…It has been suggested that this exists persistently because twins are immunologically tolerant to each other and it has been suggested that this phenomenon is more common than expected. 12 Although this phenomenon was also reported among dichorionic twins, 13 such cases are rare because anastomotic communication is rarely found within dichorionic placentas. 14 We have experienced two cases of monochorionic dizygotic twins, including the current case, among 89 monochorionic pregnancies since 2003.…”

The First Known Case of Blood Group Chimerism in Monochorionic Dizygotic Twins in Korea

“…To date, there is no report on MC DZT exhibiting blood group chimerism in Korea. There has been only one reported instance of blood group chimerism in a dizygotic dichorionic pregnancy, even though IVF-ET is widely used in Korea [2, 4]. We report blood group chimerism in sex-discordant MC DZT conceived via IVF-ET, initially misdiagnosed at birth as having blood subgroup B3.…”

Unusual twinning: Additional findings during prenatal diagnosis of twin zygosity by single nucleotide polymorphism (SNP) array

“…Phelan et al suggested that vascular anastomoses in the placenta might have important implications for the “vanishing twin” phenomenon and could convert a dichorionic twin pregnancy to a singleton pregnancy, which has rarely been observed in placentas after delivery. However, abnormal findings such as discordant amniotic fluid volumes, structure defects, and blood chimerism may indicate vascular connections in dichorionic twin placentas. Therefore, when 1 of 2 fetuses have structural defects, discordant amniotic fluid volumes, or blood chimerism, we suggest that accurate twin zygosity diagnosis be performed before selective reduction and that vascular anastomoses should be considered in dichorionic placentas.…”

“…However, abnormal findings such as discordant amniotic fluid volumes, structure defects, and blood chimerism may indicate vascular connections in dichorionic twin placentas. Therefore, when 1 of 2 fetuses have structural defects, discordant amniotic fluid volumes, or blood chimerism, we suggest that accurate twin zygosity diagnosis be performed before selective reduction and that vascular anastomoses should be considered in dichorionic placentas.…”