Sirenomelia with oligodactylia: early ultrasonographic and hysteroscopic embryoscopic diagnosis during the first trimester of gestation.

The case we describe reports the early sonographic findings of sirenomelia with oligodactylia at 9 weeks of gestation by transvaginal two-dimensional color Doppler ultrasonography imaging and its confirmation by hysteroscopic embryoscopy at 12 weeks to further characterize the findings. The embryo showed increased nuchal translucency and fused lower limbs with a large intra-abdominal vessel and two-vessel umbilical cords. The pregnancy was terminated by medical abortion induction after the patient viewed the embryoscopic images. Diagnosis is commonly made later in the second trimester of pregnancy, oligohydramnios being a warning signal, which usually makes the diagnosis difficult. Survival, only possible in the absence of renal agenesis, is extremely rare. In view of the extremely poor prognosis, early diagnosis allows for earlier counseling and less traumatic therapeutic termination of pregnancy.