The Prenatal and Postnatal Incidence of Congenital Anomalies of the Kidneys and Urinary Tract (CAKUT) Detected by Ultrasound

Purpose: Congenital anomalies of the kidneys and urinary tract (CAKUT) are the most common anomalies identified in newborns. This study aims to demonstrate the prevalence of CAKUT including hydronephrosis diagnosed by antenatal and postnatal ultrasound over a five-year period. Methods: The records of births between May 1, 2009 and April 30, 2014 at our hospital were collected. The number of infants who underwent renal ultrasound after birth for the detection of CAKUT was counted. The incidence of each type of CAKUT such as hydronephrosis, size abnormality, horseshoe kidney, and Multi cystic dysplastic kidney (MCDK) was retrospectively evaluated for antenatal screening and postnatal follow-up examination. Results: During the study period, 33,276 infants were born and 521 neonates underwent postnatal renal ultrasound. 183 cases of CAKUT were detected prenatally and 140 postnatally using ultrasonographic examinations at the following time: (i) 3-7 days postnatally in 123 newborns (87.9%), (ii) during 1-3 months in 11 newborns (7.9%), and (iii) later than 3 months in 6 newborns (4.3%). Among diagnosed CAKUT, hydronephrosis was the most common anomaly with 113 newborns diagnosed prenatally and 46 postnatally. Duplex kidney was the second most common anomaly followed by horseshoe kidney, simple cysts in the kidney and so on. Conclusion: The detection of CAKUT is an important part of the prenatal ultrasound. This study analyzed the prevalence of CAKUT detected on prenatal screening and compared the results to those detected postnatally. Prenatal ultrasound screening fulfills the needs of postnatal examinations and therefore, both antenatal and postnatal sonographic investigations are of vital importance for diagnosis of renal and urinary tract anomalies.