Conjoined twins

Abstract

Introduction: Conjoined twins are due to the late and incomplete division of the monozygotic embryonic disc that usually occurs after the twelfth day of fertilization. It is a sporadic phenomenon with a prevalence of 1 in 50,000 to 100,000 births, and it only occurs in monochorionic-monoamniotic pregnancies. Mortality rates are very high and only few cases have a sufficiently favorable
anatomy to allow and survive surgical separation.
Objectives: To report the case of a monoamniotic monochorial pregnancy of congenital twins, given its infrequent presentation in the medical practice, and to demonstrate the value of early ultrasonographic diagnosis of this type of congenital defects.
Case report: This the case of a 25-year-old nulliparous patient with health history who underwent a first trimester ultrasound of genetic markers in compliance with the provisions of the protocol for the diagnosis of chromosomal abnormalities by cytogenetic studies. The resulting diagnosis was monoamniotic monochorial pregnancy of conjoined twins of thoracopagus symmetric type. The couple was
advised on the risks of assuming a pregnancy with this pathology and they decided on the culmination of the pregnancy.
Conclusions: First trimester ultrasound as a genetic marker made possible the early diagnosis of a malformation with an unfavorable prognosis for the parents' consensual decision to discontinue the pregnancy.