Maternal hydronephrosis in normal pregnancy in Bayelsa state, South-South Nigeria


  • Peter Chibuzor Oriji Department of Obstetrics and Gynaecology, Federal Medical Centre, Yenagoa, Bayelsa State, Nigeria
  • Enefia Kelvin Kiridi Department of Radiology, Niger Delta University Teaching Hospital, Okolobiri, Bayelsa State, Nigeria Silhouette Radiodiagnostic Consultants, Yenagoa, Bayelsa State, Nigeria
  • Issac Joel Abasi Department of Obstetrics and Gynaecology, Niger Delta University Teaching Hospital, Okolobiri, Bayelsa State, Nigeria



Hydronephrosis, Pregnancy, Pelvicalyceal dilatation, Kidneys, Calculi


Background: Hydronephrosis is a common finding in normal pregnancy. It is the dilatation of the renal calyces and pelvis by urine, as a result of obstruction of the outflow of urine distal to the renal pelvis. It is usually physiological. The objective of this study was to determine the prevalence of maternal hydronephrosis, and correlate it with age, parity and gestational age in normal pregnancy in Bayelsa State, Nigeria.

Methods: This prospective study was conducted at the obstetrics and gynaecology, and radiology departments of the two tertiary hospitals in Bayelsa State, Nigeria, over a six-month period. Sonographic measurements of pelvicalyceal diameters of 400 consecutive normal pregnant women were done, after written informed consent. Data were entered into a pre-designed proforma, and analysed using Statistical Product and Service Solutions (SPSS) version 25.0. Results were presented in frequencies and percentages for categorical variables; mean and standard deviation for continuous variables; Student’s t-test to compare sample means; and Chi-square for associations.

Results: Four hundred pregnant women were scanned. Pelvicalyceal dilatation was present in 144 (36%) women; it affected one kidney in 108 (27%) women; while in 36 (9%) women, the two kidneys were affected. Renal calculi were present in 16 (4%) women. The right kidney was affected in 12 (3%) women and the left kidney in 4 (1%) women.

Conclusions: The prevalence of hydronephrosis in this study is lower than that from many centres. Pelvicalyceal dilatation was more on the right, and the degree of dilatation increased with increasing gestational age.


Medscape. Hydronephrosis and Hydroureter: Pathophysiology, Epidemiology. Practice Essentials, 2022. Available at Accessed 8 February 2022.

Radiopaedia. Maternal hydronephrosis in pregnancy. Radiology Reference Article, 2022. Available at Accessed 8 February 2022.

Rasmussen PE, Nielsen FR. Hydronephrosis during pregnancy: a literature survey. Eur J Obstet Gynecol Reprod Biol. 1988;27(3):249-259. doi:10.1016/0028-2243(88)90130-x

Onen A. Grading of Hydronephrosis: An Ongoing Challenge. Front Pediatr. 2020;8:458. doi:10.3389/fped.2020.00458

Namdev R. Hydronephrosis grading (SFU system). Radiology Reference Article, 2021. Radiopaedia. Available at Accessed 8 February 2022.

Fainaru O, Almog B, Gamzu R, Lessing JB, Kupferminc M. The management of symptomatic hydronephrosis in pregnancy. BJOG. 2002;109(12):1385-1387. doi:10.1046/j.1471-0528.2002.01545.x

Araoye MO. Subjects Selection. In: Research Methodology with statistics for Health and Social sciences. Ilorin: Nathadex publishers; 2003:115–129.

Grosjean J, Cannie M, de Meyer JM. Physiological hydronephrosis in pregnancy: Occurrence and possible causes. An MRI study. Progres En Urol J Assoc Francaise Urol Soc Francaise Urol. 2017;27(12):603-608. doi:10.1016/j.purol.2017.07.241

Fernbach SK, Maizels M, Conway JJ. Ultrasound grading of hydronephrosis: introduction to the system used by the Society for Fetal Urology. Pediatr Radiol. 1993;23(6):478-480. doi:10.1007/BF02012459

Oyinloye OI, Okoyomo OO. Evaluation of hydronephrosis, during pregnancy in Nigerian women. Niger J Clin Pract. 2010;13(1):51-54. doi:10.4314/njcp.v13i1.53186

Ciciu E, Paṣatu-Cornea AM, Petcu LC, Tuţă LA. Early diagnosis and management of maternal ureterohydronephrosis during pregnancy. Exp Ther Med. 2022;23(1):27. doi:10.3892/etm.2021.10949

Peake SL, Roxburgh HB, Langlois SL. Ultrasonic assessment of hydronephrosis of pregnancy. Radiology. 1983;146(1):167-170. doi:10.1148/radiology.146.1.6849041

Cietak KA, Newton JR. Serial qualitative maternal nephrosonography in pregnancy. Br J Radiol. 1985;58(689):399-404. doi:10.1259/0007-1285-58-689-399

Mandal D, Saha MM, Pal DK. Urological disorders and pregnancy: An overall experience. Urol Ann. 2017;9(1):32-36. doi:10.4103/0974-7796.198901

The S, Chan LW. Pelvicalyceal dilatation in maternal kidneys during normal pregnancy – an uncommon finding? J Urol. 2008;179(4S):726-726. doi:10.1016/S0022-5347(08)62117-5

Wadasinghe SU, Metcalf L, Metcalf P, Perry D. Maternal Physiologic Renal Pelvis Dilatation in Pregnancy: Sonographic Reference Data. J Ultrasound Med Off J Am Inst Ultrasound Med. 2016;35(12):2659-2664. doi:10.7863/ultra.15.12036

Bayraktar Z, Kahraman ŞT, Alaç ES, Yengel İ, Sarıkaya Kalkan D. Maternal hydronephrosis in pregnant women without ureteral stones and characteristics of symptomatic cases who need treatment: A single-center prospective study with 1026 pregnant women. Arch Ital Urol Androl Organo Uff Soc Ital Ecogr Urol E Nefrol. 2021;93(1):35-41. doi:10.4081/aiua.2021.1.35

Puskar D, Balagović I, Filipović A, Knezović N, Kopjar M, Huis M, et al. Symptomatic physiologic hydronephrosis in pregnancy: incidence, complications and treatment. Eur Urol. 2001;39(3):260-263. doi:10.1159/000052449

Eckford SD, Gingell JC. Ureteric obstruction in pregnancy--diagnosis and management. Br J Obstet Gynaecol. 1991;98(11):1137-1140. doi:10.1111/j.1471-0528.1991.tb15366.x

Zwergel T, Lindenmeir T, Wullich B. Management of acute hydronephrosis in pregnancy by ureteral stenting. Eur Urol. 1996;29(3):292-297. doi:10.1159/000473763






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