A Case of Type I Sirenomelia Complicated by Severe Oligohydramnios in the First Trimester

Table 1

Possible associated abnormalities with sirenomelia.

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Urogenital

 Renal agenesis

 Multicystic dysplastic kidneys (rare)

 Genital ambiguity/absence of external genitalia

 Müllerian anomalies

 Cloacal abnormalities

Gastrointestinal tract

 Anorectal atresia

 Sacral agenesis

Skeletal

 Neural tube defects

 Lumbosacral dysgenesis/agenesis

 Sacral agenesis

 Varying degrees of limb reduction, soft tissue fusion of lower extremities, single lower extremity

 Hypoplasia/aplasia of pelvic girdle

 Complex fusion of feet (sympodia)

 Absent feet

 Radial ray abnormalities

 Phocomelia

 Rotational abnormalities of lower limbs

 Hip dislocation

Others

 Single umbilical artery (virtually always present)
 Vestigial tail

Cardiac system anomalies (less common)

Central nervous system anomalies (less common)

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Listed based on Reference [6].