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 Table of Contents  
Year : 2022  |  Volume : 11  |  Issue : 3  |  Page : 150-153

Occurrence of vesicoureteral reflux among the antenatally detected urinary tract dilation/antenatal hydronephrosis

1 Department of Pediatrics, Government Medical College, Srinagar, Jammu and Kashmir, India
2 Department of Pediatric Nephrology, Government Medical College, Srinagar, Jammu and Kashmir, India

Date of Submission03-Feb-2022
Date of Decision13-May-2022
Date of Acceptance14-May-2022
Date of Web Publication06-Jul-2022

Correspondence Address:
Naseer Yousuf Mir
Department of Pediatrics, Government Medical College, Srinagar, Jammu and Kashmir
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jcn.jcn_14_22

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Background: Approximately 1% of pregnancies on obstetric ultrasound (US) are associated with structural fetal anomalies, among whom 20% are of the genitourinary system. Objective: The objective of this study was to determine the occurrence of vesicoureteral reflux (VUR) among the antenatally detected urinary tract dilation (UTD)/antenatal hydronephrosis (ANH) on postnatal follow-up. Methods: The study was a prospective observational study where the presence of anterior-posterior renal pelvis diameter (APRPD) of the fetal kidneys on obstetric ultrasound of >4 mm in the second trimester or >7 mm in the third trimester was taken to diagnose UTD/ANH were enrolled for the follow-up of successive US scans postnatally on the 7th, 30th, and 45th day of life. Patients with APRPD >4 mm postnatally, were subjected to micturating cystourethrogram (MCUG) at or after 45 days of life. Results: A total of 61,587 pregnant women visited the outpatient department, among whom 10,800 pregnant women underwent US scanning for fetal well-being during the second trimester, where 119/10,800 (1.1%) had UTD/ANH. A total of 21 patients were excluded from the study for various reasons and 98 patients were on follow-up. Postnatally on the 7th day of life, UTD/hydronephrosis (HDN) was detected in 41/98 (41.8%), as 57/98 (58.2%) neonates had no UTD/HDN. VUR was detected in 21/98 (21.4%) on MCUG. Conclusion: Around three-fifth of fetal UTD/ANH had a spontaneous resolution, whereas 2/5th has persistent UTD/HDN. Moderate and severe UTD/ANH infants possess a high risk of VUR as was observed in the present study and mandates a careful follow-up, to avoid any medical/surgical eventuality.

Keywords: Fetal hydronephrosis, incidence, ultrasound, urinary tract dilation, vesicoureteral reflux

How to cite this article:
Ahmed I, Ashraf M, Mir NY, Andrabi SA. Occurrence of vesicoureteral reflux among the antenatally detected urinary tract dilation/antenatal hydronephrosis. J Clin Neonatol 2022;11:150-3

How to cite this URL:
Ahmed I, Ashraf M, Mir NY, Andrabi SA. Occurrence of vesicoureteral reflux among the antenatally detected urinary tract dilation/antenatal hydronephrosis. J Clin Neonatol [serial online] 2022 [cited 2022 Nov 27];11:150-3. Available from: https://www.jcnonweb.com/text.asp?2022/11/3/150/350028

  Introduction Top

The widespread use of obstetric US during pregnancy has resulted in a high detection of fetal urinary tract dilation (UTD)/antenatal hydronephrosis (ANH). UTD/ANH accounts 1%–2% of obstetrical ultrasound (US) examinations.[1] Infants with UTD/HDN are usually normal at birth; however, it can be posterior urethral valve, pelviureteric junction obstruction, vesicoureteral reflux (VUR), renal hypoplasia/dysplasia, or duplex system later.[2] This puts the treating physician in a challenging position regarding the further investigation and possible intervention in selective patients to avoid any complication or disease progression.

Most commonly ultrasound screening is carried out during the second trimester (18–20 weeks of gestation) for knowing the fetal status. Visualization of the renal pelvis and calyces during this scan is considered abnormal, it indicates UTD/ANH/HDN. After delineation of renal pelvis and calyces, its degree of extent is categorized by either using APRPD system or the Society for Fetal Urology classification or UTD criteria. The present study was conducted to determine the incidence of UTD/HDN and/or vesicoureteral reflux (VUR) on follow up, among the prenatally detected UTD/ANH.

  Methods Top

This prospective observational study was conducted at G. B. Pant and LD Hospitals of Government Medical College, Srinagar, Jammu and Kashmir, India, over a period of 1 year with effect from December 2019 to November 2020. After obtaining proper consent, obstetric US was carried out as a part of antenatal checkup for all pregnant women, and all those who had fetal anterior-posterior renal pelvis diameter (APRPD) was >4 mm in the second trimester or >7 mm in the third trimester were enrolled for the study. The categorization of UTD/ANH/HDN was done according to the APRPD as follows: normal (0–4 mm), mild UTD/ANH/HDN (5–9 mm), moderate UTD/ANH/HDN (10–15 mm), and severe UTD/ANH/HDN (>15 mm).[3] Postnatally, these infants were subjected to kidney and bladder US scans on the 7th, 30th, 45th day of life, and data were collected.

A postnatal US on day 7th of life was considered abnormal if suggestive of APRPD ≥4 mm, calyceal dilation, ureteral wall or pelvis thickening, ureteral dilatation (ureteral diameter >2 mm), loss of corticomedullary differentiation, or renal dysplasia/hypoplasia. All patients except mild degree of unilateral UTD/HDN were put on antibiotic prophylaxis using amoxicillin (10 mg/kg/day), from birth. The antibiotic prophylaxis was discontinued in patients without VUR on MCUG taken on the 45th day of life or later and in those with APRPD <10 mm. VUR was graded by the International Reflux Study in the children classification system.[4]

The children with persistence of a dilatation were followed with repeated ultrasounds at 3 and 6 months after birth. The clinical course at 6 months was analyzed and recorded for all children either by means of the clinical follow-up or a phone questionnaire for patients whose follow-up was stopped at 1 month. The postnatal ultrasound examinations were performed by senior radiologist using Seimens Acuson X-300, USA, Model-KT-LM-200 HDPE.

Statistical methods

The data were entered into Microsoft Excel 2010 and analyzed using the Statistical Package for the Social Sciences (SPSS version 23), operating system(s): AIX, iOS, Solaris, Windows. The categorical variables were described as frequency and percentage. The Chi-square test was used to see the association between two categorical variables. Whenever Chi-square was not feasible, Fisher's exact test was used in its place. P = 0.05 was considered to be statistically significant.

  Results Top

A total of 10,800 underwent obstetric US, for fetal well-being, and 119 fetuses were detected to have UTD/ANH. Out of 119 patients, 21 were excluded from the study, as 15 neonates lost the follow-up, whereas 6 refused to undergo MCUG. UTD/ANH resolved in 10 in the third trimester reducing the total to 88, for postnatal follow-up. The timeline and follow-up details are shown in [Table 1], while obstetric US findings during the second trimester are shown in [Table 2].
Table 1: Depicts the timeline regarding the number of patients with urinary tract dilation/antenatal hydronephrosis, and postnatal spontaneous resolution, from the second trimester to 6 months of extrauterine life

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Table 2: Neonatal confirmation of fetal urinary tract dilation (antenatal hydronephrosis) at second trimester on ultrasonography

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  Discussion Top

In the present study, obstetric US were performed at the second trimester of pregnancy and third trimester of pregnancy considering APD at the second trimester ≥4 mm and ≥7 mm in the third trimester as the diagnostic criteria for further follow-up. A fetal UTD/ANH/HDN incidence of 0.9% (98/10080) was observed, which is comparable with the study conducted by Ek et al. (1%),[5] Dudley et al. (0.59%),[6] and Sairam et al. (2.3),[7] but much lower than the studies conducted by Persutte et al. (5.5%)[8] and Gunn et al. (7.8).[9]

In our study, ANH was detected more commonly in males 71/88 (80.6%) than females 17/88 (19.3%) and male-to-female ratio was 4.1 which is consistent with the finding of earlier studies.[10],[11],[12]

In our study, 66/98 (67.35%) had mild UTD/ANH, 19/98 (19.3%) had moderate, whereas 13/98 (13.2%) had severe degree of UTD/ANH [Table 3] which is comparable with the study conducted by Afroz et al.,[13] who observed 70 (63%) had mild, whereas 26 (23.42%) moderate and 15 (13.5%) had severe degree of UTD/ANH, respectively. Nevertheless, Sairam et al.[7] found that mild hydronephrosis was present in 80.6% (216/268) and moderate/severe hydronephrosis in 19.4% (52/268) patients.
Table 3: Relationship between the degree of fetal urinary tract dilation (antenatal hydronephrosis) and vesicoureteral reflux

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Renal pelvic dilatation resolved antenatally on follow-up scan in 10 (10.2%) patients which is comparable with the study conducted by Shamshirsaz et al.[14] (15.09%), but UTD resolution rate was far lesser when compared to the study conducted by Gunn et al.[9] 216/301 (72%) and Sairam et al.[7] 48/75 (64%). First postnatal ultrasound scans on the 7th day of extrauterine life showed normalization of APRPD in 58 patients (59.18%). Resolution at 6 months of life was 87.5% which is comparable with the study conducted by Gunn et al.[9] (72%), but higher than the study conducted by Sairam et al.[7] (67%) and Dudley et al.[6] (31.25%).

The incidence of VUR on MCUG at the 45th day of postnatal life was 21/98 (21.4%), among whom 1/98 (1.0%) had mild UTD/HDN, whereas 10/41 (20.4%) had moderate and severe UTD/HDN each, which is consistent with findings of Tibballs and De Bruyn[15] (18.4%); however, it is lower than the VUR incidence reported by Marra et al.[16] (30%) and Mohammadjafari et al.[17] (29.7%).

Diethylenetriamine Pentaacetic Acid (DTPA) was done in patients with normal MCUG, but had persistent UTD/HDN with APRPD>15mm, many of them we lost to follow-up, after seeking pediatric surgery/urology consult, hence were excluded them from our study.

Patients with VUR are on follow up and most of them are on antibiotic prophylaxis and few with higher grade VUR had breakthrough urinary tract infections and had undergone ureteric reimplantation.

  Conclusion Top

Mild degree of fetal UTD/ANH is a transient phenomenon in the majority of cases, however, moderate-to-severe UTD/ANH does require careful follow-up postnatally as they are at higher risk for poor outcomes. The presence of VUR is a significant risk factor for adverse outcomes.

What this study adds to literature

Being an observational study our finding complement the already existing literature, as we conclude that majority of mild degree of prenatal and postnatal UTD/ANH/HDN are transient, however, missed opportunity to detect and treat moderate to severe degree of UTD/ANH/HDN may prove a medical or surgical catastrophe.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Hamilton BE, Martin JA, Ventura SJ. Births: Preliminary data for 2012. Natl Vital Stat Rep 2013;62:1-20.  Back to cited text no. 1
Dillon E, Walton SM. The antenatal diagnosis of fetal abnormalities: A 10 year audit of influencing factors. Br J Radiol 1997;70:341-6.  Back to cited text no. 2
Sinha A, Bagga A, Krishna A, Bajpai M, Srinivas M, Uppal R, et al. Revised Guidelines on Management of Antenatal Hydronephrosis. Indian Pediatr 2013;50:215-31.  Back to cited text no. 3
Lebowitz RL, Olbing H, Parkkulainen KV, Smellie JM, Tamminen-Möbius TE. International system of radiographic grading of vesicoureteric reflux. International reflux study in children. Pediatr Radiol 1985;15:105-9.  Back to cited text no. 4
Ek S, Lidefeldt KJ, Varricio L. Fetal hydronephrosis; prevalence, natural history and postnatal consequences in an unselected population. Acta Obstet Gynecol Scand 2007;86:1463-6.  Back to cited text no. 5
Dudley JA, Haworth JM, McGraw ME, Frank JD, Tizard EJ. Clinical relevance and implications of antenatal hydronephrosis. Arch Dis Child Fetal Neonatal Ed 1997;76:F31-4.  Back to cited text no. 6
Sairam S, Al-Habib A, Sasson S, Thilaganathan B. Natural history of fetal hydronephrosis diagnosed on mid-trimester ultrasound. Ultrasound Obstet Gynecol 2001;17:191-6.  Back to cited text no. 7
Persutte WH, Koyle M, Lenke RR, Klas J, Ryan C, Hobbins JC. Mild pyelectasis ascertained with prenatal ultrasonography is pediatrically significant. Ultrasound Obstet Gynecol 1997;10:12-8.  Back to cited text no. 8
Gunn TR, Mora JD, Pease P. Antenatal diagnosis of urinary tract abnormalities by ultrasonography after 28 weeks' gestation: Incidence and outcome. Am J Obstet Gynecol 1995;172:479-86.  Back to cited text no. 9
Anderson N, Clautice-Engle T, Allan R, Abbott G, Wells JE. Detection of obstructive uropathy in the fetus: Predictive value of sonographic measurements of renal pelvic diameter at various gestational ages. AJR Am J Roentgenol 1995;164:719-23.  Back to cited text no. 10
Coelho GM, Bouzada MC, Pereira AK, Figueiredo BF, Leite MR, Oliveira DS, et al. Outcome of isolated antenatal hydronephrosis: A prospective cohort study. Pediatr Nephrol 2007;22:1727-34.  Back to cited text no. 11
Chaudhary S, Shah AK. Assessing outcome of antenatal hydronephrosis – An integrated clinical approach. J Evid Based Med Healthc 2018;5:1069-74.  Back to cited text no. 12
Afroz R, Shakoor S, Salat MS, Munim S. Antenatal renal pelvic dilatation and foetal outcomes – Review of cases from a tertiary care center in Karachi, Pakistan. J Pak Med Assoc 2016;66:1597-601.  Back to cited text no. 13
Shamshirsaz AA, Ravangard SF, Egan JF, Prabulos AM, Shamshirsaz AA, Ferrer FA, et al. Fetal hydronephrosis as a predictor of neonatal urologic outcomes. J Ultrasound Med 2012;31:947-54.  Back to cited text no. 14
Tibballs JM, De Bruyn R. Primary vesicoureteric reflux – How useful is postnatal ultrasound? Arch Dis Child 1996;75:444-7.  Back to cited text no. 15
Marra G, Barbieri G, Moioli C, Assael BM, Grumieri G, Caccamo ML. Mild fetal hydronephrosis indicating vesicoureteric reflux. Arch Dis Child Fetal Neonatal Ed 1994;70:F147-9.  Back to cited text no. 16
Mohammadjafari H, Alam A, Kosarian M, Mousavi SA, Kosarian S. Vesicoureteral reflux in neonates with hydronephrosis: Role of imaging tools. Iran J Pediatr 2009;19:347-53.  Back to cited text no. 17


  [Table 1], [Table 2], [Table 3]


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