Fetal hydronephrosis as a predictor of neonatal urologic outcomes.
OBJECTIVE
The ability to predict surgically relevant fetal renal hydronephrosis is limited. We sought to determine the most efficacious second- and third-trimester fetal renal pelvis anteroposterior diameter cutoffs to predict the need for postnatal surgery.


METHODS
We retrospectively reviewed the medical records of mothers and neonates who had a prenatal sonographic examination in our Perinatal-Pediatric Urology Clinic and received follow-up care. Hydronephrosis was defined as a renal pelvis anteroposterior diameter of 5 mm or greater in the second trimester and 7 mm or greater in the third trimester. Hydronephrosis was subdivided into mild, moderate, and severe.


RESULTS
Of 8453 fetuses, 96 met the criteria and were referred to our clinic. Isolated hydronephrosis was diagnosed in 74 fetuses, of which 53 received postnatal follow-up evaluations. The areas under the receiver operating characteristic curves for predicting postnatal surgery in the second and third trimesters were 0.770 and 0.899, respectively. The second-trimester renal anteroposterior diameter threshold that best predicted post-natal surgery was 9.5 mm (sensitivity, 71.4%; specificity, 81.1%). The third-trimester threshold that best predicted postnatal surgery was 15.0 mm (sensitivity, 85.7%; specificity, 94.6%).


CONCLUSIONS
The fetal renal anteroposterior diameter on second- and third-trimester sonography is predictive of an increased risk for neonatal urologic surgery. Surgical risk is best predicted by a third-trimester renal anteroposterior diameter threshold of 15 mm.
Department of Obstetrics and Gynecology, University of Connecticut Health Center, 263 Farmington Ave, Farmington, CT 06030, USA. alirezashamshirsaz@yahoo.com
Alireza A
AA
Shamshirsaz
Samadh F
SF
Ravangard
James F
JF
Egan
Ann Marie
AM
Prabulos
Amirhoushang A
AA
Shamshirsaz
Fernando A
FA
Ferrer
John H
JH
Makari
Heidi K
HK
Leftwich
Katherine W
KW
Herbst
Rachel A
RA
Billstrom
Allison
A
Sadowski
Padmalatha
P
Gurram
Winston A
WA
Campbell
D003237:Connecticut / Q000453:epidemiology; D006801:Humans; D006869:Hydronephrosis / Q000151:congenital / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D007668:Kidney / Q000000981:diagnostic imaging*; D009929:Organ Size; D015995:Prevalence; D011379:Prognosis; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000706:statistics & numerical data*