Introduction
Flank pain is a clinical condition occurring as well as in pregnancy and causes frequent emergency room (ER) visits. Most of the pregnant women presenting with flank pain might have hydronephrosis.(1) During the course of pregnancy mild hydronephrosis is reported in 90% of the patients. It is more frequently experienced by the nulliparous (1-3). In pregnancies, hydronephrosis mostly develops in the right kidney and might cause pyelonephritis and urosepsis (4). More frequent occurrence on the right side is ascribed to dextrorotation of the uterus and protection of the left ureter by the sigmoid colon.(5) It has been asserted that in the mechanism of hydronephrosis formation, in addition to uterine compression, is progesterone hormone’s relaxing effect on the smooth muscle.(6, 7) In many studies, such issues as urinary stone disease causing urinary obstruction and urinary tract infection secondary to ureteric obstruction have been addressed.(4) Although hydronephrosis may be seen in 90% of pregnancies, in most of the cases they are observed without any symptoms.(5, 8) Some of these patients may present with severe flank pain, recurrent urinary tract infections and even renal dysfunction.(5) Most of the patients benefit from conservative approach and medical treatment. However, invasive procedures such as ureteral stent or renal nephrostomy may be needed in 6%. (5, 9)
In this study, factors other than pregnancy such as ureteral stones and urinary tract infection that might cause hydronephrosis and pain were excluded. We aimed to investigate the relationship between nulliparity and multiparity with hydronephrosis and pain, as well as the relationship between the degree of hydronephrosis and pain.