Sudden intrauterine unexplained death syndrome (SIUDS): Fetal and placental autopsy is strongly recommended for evaluating the cause of pregnancy failure

Purpose: Clinical risk factors of sudden intrauterine unexplained death syndrome (SIUDS) in late pregnancy have been identified. But, the reasons for SIUDS, determined by autopsy are not well established yet.

Methods: Fetuses with clinically unexplained intrauterine death were obtained from the files of the Institute of Pathology, Dept. of Perinatal- & Gynecologic Pathology of the Univeristy of Leipzig to determine the causes of intrauterine death.

Results: Out of 51 cases twelve cases fulfilled the criteria of SIUDS >30th weeks of gestation without any known clinical risk factors for intrauterine death. The mean pregnancy age was 36.5 weeks, the mean maternal age 32.4 years. Two thirds of the fetuses represented with intrauterine growth restriction. Causative for intrauterine death was placental dysmaturity in 11/12 cases. One SIUD was caused by thin-cord-syndrome.

Conclusions: Chronic placental failure as the main cause of IUR is a main risk factor for SIUDS. Acute placental failure because of placental dysmaturity can be identified in most cases of SIUDS. So, fetal and placental autopsy may highlight the causes for SIUDS.