Discussion
This study with prospectively evaluated pregnant women demonstrated that the degree of hydronephrosis and the number of pregnancies correlated with the severity of pain. While our findings are similar with the literature at some points, they seem to support the opposite view with some others. The incidence of acute flank pain and hydronephrosis more on the right side is consistent with the literature.(4, 5, 10) Some studies reported that hydronephrosis is more common especially in primigravidae (1, 5). In our study, especially in the nulliparous, hydronephrosis and pain were found to have medium level, positive correlation. In the literature there are studies which state that hydronephrosis is common in pregnant women; that there is no relationship between hydronephrosis and acute flank pain and that most cases develop asymptomatically(5, 8). Farr et al. reported that hydronephrosis was not observed in some of the patients with flank pain.(11). In the same study, Farr et al. stated there was no correlation between hydronephrosis and pain intensity(11). Many studies in the literature investigated hydronephrosis and its prevalence and the relationship between hydronephrosis and pain. The main difference in our study was that all patients were admitted with acute flank pain. Detection of hydronephrosis in all the pregnant women included in our study made us consider hydronephrosis to be associated with acute flank pain. It is also possible that anatomic factors and gestational anxiety might have been effective in the positive correlation between the pain and the degree of hydronephrosis and in higher VAS scores of the nulliparous than the multiparous (12). In lack of concrete evidence such as psychiatric examination results, we think that this may be subject of another study.
In the literature, cases of complicated urinary tract infection such as pyelonephritis that developed during and after the second trimester and causing serious complications were reported (13). No patients with urinary tract infection were included in our study and none of the patients included in the study developed pyelonephritis later. The majority of patients (91.7%) benefited from conservative treatment. Only 4 patients (8.3%) underwent ureteral JJ stent placement. This ratio is consistent with the literature, yet the small number of patients is a limiting factor for a strong interpretation(5).
The most important difference that distinguish our study from other studies is the comparison between multipar and nulliparous patients and assessing only the relationship between flank pain and degree of hydronephrosis. In some studies, patients with symptom like fever and signs like WBC and CRP increase were included to study(14). In contrast to these studies, patients who had only flank pain and normal biochemical tests but had no symptoms like fever were included to our study. We think that our study also enables a stronger evaluation for the relationship between hydronephrosis and flank pain without different symptoms and signs. In some studies, it has been reported that hydronephrosis is common during pregnancy and is asymptomatic (5, 8). However, patients with mild hydronephrosis were also included in these studies, and pregnant women with mild hydronephrosis constitute the vast majority. In our study, there are patients in the late periods of the second trimester and in the third trimester. As a result, we think that hydronephrosis increases with the progression of pregnancy and pain associated with it is observed.
As we were the only urology center in the city, all patients were followed up by the same team. Ureteral JJ stent placed in one of the patients was removed before delivery and the other three stents were removed about 3-4 weeks after delivery. Removal of one of the stents before delivery was done upon the demand of the patient due to hematuria and irritative stent symptoms. No major complication developed in the patients with ureteral JJ stents. Although we cannot make a strong interpretation due to the small number of patients, this result is consistent with the literature (15). The degrees of hydronephrosis in the patients who were placed stents were grade 2 and grade 3 (n = 1, n = 3, respectively) and their VAS scores were 9 and 10 (n = 2, n = 2, respectively). In concurrence with the study of Tsai et al. we think that JJ stent is more effective than conservative treatment in pregnant women with advanced hydronephrosis (15). JJ stents may be applied as a reliable method in these patients. The most important limiting factor of our study was the number of patients. A stronger result could be obtained with more patients. Birth and postnatal data of the patients included in our study are not available as well.