TAPS sequence – unknown and underestimated problem of monochorionic pregnancies

Abstract

Monochorionic twin pregnancy is associated with an increased perinatal morbidity and mortality. Placental anastomoses are typical for monochorionic pregnancies and may play a role in the development of severe complications such as twin-twin transfusion syndrome (TTTS) and recently discovered twin anemia-polycythemia sequence (TAPS). Both TTTS and TAPS are the chronic form of feto-fetal transfusion. There is a typical oligohydramnios/polyhydramnios sequence in the TTTS syndrome, whereas TAPS is characterized by large intertwine hemoglobin difference in the absence of amniotic fluid discordances. The paper presents a case of TAPS at 20 weeks of gestation in a 35-year-old primigravida with monochorionic, diamniotic pregnancy. TAPS was the cause of Intrauterine fetal death of one of the twins. In the absence of signs of fetal distress an expectant management was considered. An elective cesarean section was performed at 35 weeks of gestation due to decelerations in CTG. This paper presents a clinical case, as well as diagnostic criteria, classification, perinatal management and outcome in TAPS. The review of the literature is also included, focusing on the diagnostic differences between TAPS and TTTS, two distinct variants of feto-fetal transfusion. This case presents a twin anemia-polycythemia sequence, a rare and heterogeneous disease with a wide range of outcome. TAPS may remain undetected during pregnancy and result in the delivery of two healthy neonates with large inter-twin hemoglobin discordance. Unfortunately, TAPS may also lead to intrauterine fetal demise of one or both twins, particularly in cases when it is undetected and untreated.