Sirenomelia in a monoamniotic twin: a case report.

BACKGROUND

Sirenomelia is a rare congenital malformation characterized by fusion of the lower extremities and is associated with renal agenesis and absent bladder. Oligohydramnios usually occurs early in pregnancy.

CASE: A 21-year-old primigravida with a twin gestation was diagnosed with sirenomelia in 1 of the twins at 18 weeks; they were delivered at 34 weeks. The infant was in perfect respiratory condition, lived for 5 days and died of nonpulmonary causes.

CONCLUSION

Absence of oligohydramnios in monoamniotic twins allows free movement of the fetus in utero, facilitates the visualization of fetal organs on ultrasound and aids early prenatal diagnosis. It also delays the death of the sirenomelia infant due to the improved respiratory condition.