Proposal of a novel index in assessing perinatal mortality in prenatal diagnosis of Sacrococcygeal Teratoma.

Objectives: To describe obstetric characteristics and perinatal outcomes in a serie of fetuses with Sacrococcygeal Teratoma (SCT) and propose a novel index to assess postnatal mortality based on the THC ratio and the addition of the presence of polyhydramnios.

Methods: A retrospective study in a referral teaching hospital between 2013 and 2023. A descriptive analysis and a receiver operating characteristic (ROC) curve were performed to the determine the optimal cutoff value of the THC plus polyhydramnios based on optimal sensitivity and specificity.

Results: Eleven out of 15 fetuses were included in our series during the study period. The median gestational age at prenatal diagnosis was 30.9 weeks and the median gestational age at birth was 35.8 weeks. Seven patients developed polyhydramnios. There was no intrauterine death. There were four deaths after birth (36.4 %). A cutoff value of THC plus polyhydramnios higher than 3.0 was associated with postnatal mortality with 100 % sensitivity and 86 % specificity. There was no significant difference comparing TFR with THC plus polyhydramnios.

Conclusions: We report a high postnatal mortality of 36 % among fetuses with diagnosis of Sacrococcygeal Teratoma. Additionally, we propose a potential useful index associated with postnatal mortality based on the THC and the addition of polyhydramnios with a sensitivity of 100 %.