Hydronephrosis 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. Hydronephrosis can be physiological or pathological; acute or chronic; unilateral or bilateral; secondary to obstruction of the urinary tract or without obstruction.¹ In pregnancy, hydronephrosis is usually physiological, and occurs due to the compression of the ureters by the pregnant uterus. Physiological dilatation of the ureters due to the smooth muscle relaxing effect of progesterone is also implicated.²

Hydronephrosis is usually a common finding in pregnancy, and more common in the right kidney than the left kidney.^1-3 It is also more common in the primigravida, and usually starts in the second trimester of pregnancy. It resolves about six to twelve weeks post-partum. Sometimes, there can be an obstruction by a renalcalculi which may cause or complicate an already existing hydronephrosis.³Pelvicalyceal dilatation can also beassociated with upper urinary tract infection due to stasis of urine.

Ultrasound (USG) is the best modality for diagnosis and follow-up for both prenatal and post-natal hydronephrosis. It is non-invasive, easily available, fast, and low-cost; can be performed directly in bedside manner; and does not involve radiation. It shows the size of kidneys, thickness, and appearance of parenchyma (echogenicity, corticomedullary differentiation, cortical cysts), severity of hydronephrosis, ureteral dilation, and bladder anatomy.^4-7Ultrasound not only gives anatomical details but also gives some functional clues about the urinary system. Itprovides excellent diagnostic accuracy. There are two important benefits of ultrasound: It determines the severity of hydronephrosis.⁴The changes seen in the kidneys in hydronephrosis are visualized on ultrasound scan, which is also used to differentiate physiological hydronephrosis from an existing pathological hydronephrosis, like in the presence of a renal calculi.

Most of the pregnant women with hydronephrosis are asymptomatic, and are managed conservatively if discovered incidentally on ultrasound scan.⁵ However, in the presence of urinary tract infection, the patient should be treated with antibiotics. Surgical management should be considered in the presence of obstruction.

However, the condition is frequently overlooked or, if it is observed - which happens more often now due to the increased use of ultrasonography-considered pathological with subsequent further examinations and treatments. There is paucity of published local data on incidence& impact of hydronephrosis in normal pregnancy. For these reasons we found it needful to study hydronephrosis during pregnancy and to study its effect on maternal and fetal outcome.

Aim:

To assess prevalence of hydronephrosis and feto maternal outcome in pregnant women with hydronephrosis