Sirenomelia: A Case Series

Background: Sirenomelia is a rare congenital anomaly characterized by the fusion of two lower limbs, resulting in the mermaid’s tail appearance. Sirenomelia is a very rare syndrome and can be fatal to the infant. This syndrome might be sporadic or have a genetic basis. The etiology of sirenomelia is unknown but said to be multifactorial. Some maternal factors associated with sirenomelia include diabetes melitus, maternal age under 20 years and monozygote twinning.Case report: This report presented four cases of sirenomelia that occurred during 2006-2019 at Fatemieh Hospital, a tertiary maternal-neonatal center, Hamadan, Iran. All of the pregnancies were complicated by oligohydramnios. None of the mothers were younger than 20 years, and none had diabetes mellitus. Moreover, their drug history during pregnancy was negative. All newborns had low Apgar scores and died a few minutes after birth, indicating their poor outcomes. None of the cases were diagnosed prenatally, and all newborns were firstborn infants.Conclusion: Sirenimelia is a rare lethal condition, which requires prenatal diagnosis for abortion planning.