Update on the Prenatal Diagnosis and Outcomes of Fetal Bilateral Renal Agenesis

Importance Bilateral renal agenesis is a rare congenital anomaly associated with poor prognosis. Objective The aims of this article are to review and summarize evidence on prenatal diagnosis and outcomes of bilateral renal agenesis. Evidence Acquisition A search was undertaken using PubMed and ClinicalTrials.gov databases from January 1, 1998, to September 1, 2018. Search terms include "prenatal diagnosis" OR "outcomes" AND "bilateral renal agenesis." Search was limited to English language. Results Fetal ultrasonography is the primary imaging modality for prenatal diagnosis of fetal urogenital tract abnormalities. However, ultrasonography is limited by several factors; it is operator dependent and associated with small field of view, has limited soft-tissue acoustic contrast, and is also influenced by patient habitus and fetal position. Color Doppler ultrasonography can be used as an adjunct to exclude bilateral renal agenesis by visualizing renal arteries. In the literature, prenatal magnetic resonance imaging has been reported to be equal to or superior to prenatal ultrasonography. Bilateral renal agenesis with oligohydramnios/anhydramnios is associated with a poor prognosis; perinatal death occurs secondary to pulmonary hypoplasia in the majority of cases. Conclusions Ultrasonography in combination with color Doppler ultrasonography permits the fetal urinary tract to be assessed in the first and early second trimester of gestation. The magnetic resonance imaging can be used as a complementary adjunctive modality in equivocal or inconclusive ultrasonographic findings. Target Audience Obstetricians and gynecologists, family physicians. Learning Objectives After completing this activity, the learner should be able to describe the natural history of fetuses with bilateral renal agenesis; explain to patients the accuracy and limitations of the prenatal diagnosis of the anomaly; and counsel patients regarding the perinatal outcome and prognosis of fetuses with this condition.