Journal of Ultrasound in Medicine, Vol 20, Issue 10 1065-1069, Copyright © 2001 by American Institute of Ultrasound in Medicine
Evaluation and follow-up of fetal hydronephrosis
D. M. Feldman, M. DeCambre, E. Kong, A. Borgida, M. Jamil, P. McKenna and J. F. Egan
Division of Maternal-Fetal Medicine, University of Connecticut Health Center, Farmington 06030-2950, USA.
OBJECTIVE: To determine the antenatal course and neonatal follow-up of
isolated fetal hydronephrosis. METHODS: We reviewed our ultrasonography
database from January 1989 to June 1999 for all cases of unilateral or
bilateral fetal hydronephrosis that had at least 1 follow-up
ultrasonographic examination. Cases were defined as mild, moderate, or
severe depending on the renal pelvis anteroposterior diameter and
gestational age. Data were analyzed using the chi2 test with the Fisher
exact test where appropriate. Medical records were reviewed, and telephone
interviews were performed to determine which infants received follow-up
after birth. RESULTS: Of 57,966 ultrasonographic examinations in 20,049
women during the study period, 393 patients met criteria for evaluation. Of
these, 347 (88%) had fetuses with mild hydronephrosis. Most of these had
complete resolution during the pregnancy. Forty patients had fetuses
classified as having moderate hydronephrosis, and 6 patients had fetuses
with severe hydronephrosis. Of those classified as moderate hydronephrosis,
15% resolved, 25% improved, 48% remained unchanged, and 12% worsened during
the pregnancy. There were no cases of in utero resolution in the severe
group; however, 4 of 6 cases improved to moderate or mild, and 2 cases
remained unchanged. Of the cases identified prenatally, 25 received
consultation by a pediatric urologist in the newborn period, and 7 of these
required surgical intervention. CONCLUSIONS: Our population-based data
suggest that most cases of mild hydronephrosis will resolve before
delivery. In contrast, cases of moderate or severe hydronephrosis are less
likely to have resolution in utero and are more likely to worsen or remain
unchanged. Of those fetuses with persistent hydronephrosis, only a small
number required some surgical intervention after birth. This information is
useful in counseling the patient whose fetus is noted to have isolated
hydronephrosis.