title: The long-term outcome of antenatal hydronephrosis up to 15 millimetres justifies a noninvasive postnatal follow-up.
abstract: OBJECTIVE
  To assess the incidence of urinary tract infections (UTIs) and surgery in infants with different grades of antenatal hydronephrosis (ANH) and to evaluate incidence, severity and course of underlying vesicoureteral reflux (VUR).
  
  
  METHODS
  Retrospective data of 125 infants with ANH were collected. The patients were divided into two groups according to the anterior-posterior pelvis diameter: group I, 5-14 mm and group II, > or =15 mm.
  
  
  RESULTS
  UTIs developed in 4 of 106 infants from group I and 5 of 19 infants from group II. Surgical interventions were performed on 1 of 106 patients of group I and 7 of 19 patients of group II. These differences were statistically significant (p-values 0.004 and <0.001, respectively). In group I, 6 of 106 patients had VUR; none of them required surgical intervention and only two developed a UTI (one of whom also had contralateral ureteropelvic junction obstruction). Five of 19 infants in group II had underlying VUR, four of them with associated anomalies, 1 infant required surgical correction and 4 developed UTIs.
  
  
  CONCLUSIONS
  Infants with ANH up to 15 mm have a low incidence of UTIs and surgery and a low incidence and benign course of underlying VUR. Therefore, noninvasive postnatal follow-up is justified and standard voiding cystourethrography should not be performed, but only in cases of ureteric dilatation.
authors.affiliation: Department of Pediatrics, Máxima Medical Centre, Veldhoven, The Netherlands.
authors.forename: E H M
authors.initials: EH
authors.lastname: de Kort
authors.forename: S
authors.initials: S
authors.lastname: Bambang Oetomo
authors.forename: S H J
authors.initials: SH
authors.lastname: Zegers
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006869:Hydronephrosis / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011181:Postnatal Care / Q000379:methods; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014552:Urinary Tract Infections / Q000209:etiology; D014718:Vesico-Ureteral Reflux / Q000601:surgery*