A case report of hypogammaglobulinemia of monochorionic diamniotic twins due to twin to twin transfusion

Introduction: Monochorionic diamniotic twins (MD twins) are monozygotic twins that share the same placenta. The occurrence of MD twins is 34 % out of all twin pregnancies. It is known that some MD twins have connecting blood vessels within the placenta which causes disproportionate blood supply between fetuses, known as Twin-to-Twin Transfusion Syndrome (TTTS). TTTS is diagnosed by the amount of amniotic fluid present, as found through an ultrasound examination. There are many cases of circulation failure due to TTTS reported. However, there are few studies on IgG level of TTTS. Our description of a case showing hypogammaglobulinemia due to TTTS will be given below. Case: The MD twins were delivered by Caesarean section at a gestational age of 30 weeks and 4 days because TTTS was suspected. The donor was 1,081 g and IgG was 98 mg/dL at birth. The recipient was 1,523 g and IgG was 694 mg/dL at birth. Our case implies the imbalance of IgG level in MD twins due to Twin-to-Twin Transfusion although the case did not meet the criteria of TTTS. We administered immunoglobulin to the donor via a subcutaneous route. We successfully prevented the donor from infection by increasing IgG levels. Discussion: Because there are discrepancies of not only IgG but also Hb, Hct, TP, and Alb, it is assumed that IgG was transferred from the donor to the recipient. The same discrepancies were found in TTTS cases at our hospital. We compared 4 groups, this case, TTTS case, MD twins, and a monotocous case. The 4 groups were selected by their gestational ages (GA) between 28-31 that matched with GA of this case (30 weeks and 4 days) because IgG level increases as GA increases. No significant differences in IgG levels between the MD twins and the monotocous case were found. Thus, we can conclude that MD twins is not the cause of the discrepancy of IgG, but Twin-to-Twin Transfusion was the cause in this case. We constantly monitored The IgG levels of the donor to ensure that the IgG level did not drop lower than 300 mg/dL and administered immunoglobulin via subcutaneous injection 3 times in total. The recipient did not experience any infection and development was normal as of 7 months.