LAUSR

Twin-to-twin Transfusion Syndrome (TTTS) is a serious complication of monochorionic twin pregnancies. Affects about 10% to 15% of pregnancies and it is associated with high fetal and neonatal mortality, as well as cardiac and neurological morbidity in surviving fetuses. The main objective was to characterize a series of fetuses with TTTS since the pathophysiology of the syndrome is not fully understood and the clinical spectrum is broad. Post-mortem macroscopic and microscopic examination of 26 fetuses (from 2010 to 2020) with TTTS syndrome. The most frequent macroscopic findings in placenta were discrepancy in size and pallor/placental congestion. Other macroscopic findings not described in the literature were calcifications, areas of infarction and hematomas. Infarction areas and villi heterogeneity growth were the most common microscopic findings, described in the literature. Regarding the fetus, the restriction of intrauterine growth, the alteration of anthropometric parameters and the presence of a plethoric/anemic fetus were the main characteristics associated with this syndrome. The most common microscopic findings were signs of anoxia and congestive organs, already described in the literature. We also found frequently pulmonary abnormalities as new findings in our study. The results allowed the identification of TTTS aspects that can contribute to the characterization of this syndrome. Given that the progression of TTTS remains unpredictable and the mortality rate for both fetuses is 90%, it becomes increasingly important to identify strategies for diagnosing and characterizing the syndrome.