Suspected twin anemia polycythemia sequence in a dichorionic, diamniotic twin pregnancy: a case report

BACKGROUND: Twin anemia polycythemia sequence is a rare complication in monochorionic twin pregnancy. CASE PRESENTATION: We describe a case of dichorionic twin pregnancy presenting with suspected twin anemia polycythemia sequence. A 31-year-old White female, on her third pregnancy, had a routine ultrasound scan at 12 weeks gestation, which demonstrated a dichorionic twin pregnancy with one placenta located in the anterior wall and the other in the posterior wall of the uterus. At 21 weeks, a scan demonstrated a 24% growth discordance between the two fetuses with normal Doppler studies and amniotic fluid. At 27 weeks, one twin showed signs of anemia and the other polycythemia; the fetal middle cerebral artery peak systolic velocity was high in the anemic fetus and low in the polycythemic twin (1.8 and 0.5 multiples of the median). An intrauterine blood transfusion was carried out and this increased the fetal hemoglobin concentration in the anemic twin from 3.5 to 12.5 g/dL. At 29 weeks, delivery by cesarean section was carried out because of evidence from middle cerebral artery peak systolic velocity of recurrence of anemia in one twin and worsening polycythemia in the co-twin; at birth the hemoglobin concentrations were 5.6 and 24.9 g/dL, respectively. Histopathological examination confirmed dichorionicity with no communicating vessels between the two placentas. CONCLUSIONS: This is the first case of twin anemia polycythemia sequence in a dichorionic, diamniotic twin pregnancy where intrauterine blood transfusion was used to prolong the pregnancy by almost 2 weeks in a “twin anemia polycythemia sequence-like” setting.