What is it?

Renal agenesis refers to the absence of one or both kidneys.

How common is it?

Unilateral renal agenesis is fairly common and affects 1 in 1,000 births, whereas bilateral renal agenesis occurs in about 1 in 4,000 to 7,000 pregnancies.

How is it managed?

Unilateral renal agenesis may be associated with other anomalies of the urinary tract, intestinal tract, or heart, and may be an element of many syndromes. When identified, a detailed anatomical ultrasound and a specialized ultrasound focusing on the fetal heart (“echocardiogram”) should be performed to evaluate for co-existing anomalies. A consultation with a geneticist and discussion of genetic testing options are also recommended.

A pregnancy with isolated unilateral renal agenesis will be managed in much the same way as any other pregnancy.


After birth, special imaging will be performed to confirm the prenatal diagnosis. Unfortunately, many cases with bilateral renal agenesis will not survive the pregnancy, and those that do will pass away shortly after birth. Unilateral renal agenesis, on the other hand, is associated with an excellent outcome. Unilateral renal agenesis is often asymptomatic and associated with a normal lifespan.