Are changes in urinary parameters during pregnancy clinically significant?

We aimed to objectively determine changes in the various urinary parameters along with CaOx saturation level during pregnancy. The study included 15 pregnant women who had no known diseases and were taking no medication except prenatal supplements. Mean age of the patients was 26 years (range 20-30). In all of them, this study was carried out in each trimester and 3 months post partum. All participants were followed up, and blood and urine samples were obtained during the pregnancy and during 3 months post partum. All subjects collected 24-h urine samples. The pregnant women had hypercalciuria in all three trimesters. Except for the first trimester, urine calcium levels in all trimesters were significantly higher when compared with the post-partum period (P<0.01 for second trimester, P<0.05 for third trimester). Urine oxalate level in post-partum period was significantly higher than urine oxalate levels in each trimester (P<0.05). The urine citrate levels were similarly higher than normal levels in three trimesters. Urine citrate level of the post-partum period was in normal reference ranges. This difference was not statistically significant (P>0.05). We believe that hypercalciuria encountered at pregnancy is a reversible physiologic condition. Also, citrate and magnesium as urinary inhibitors increased in urine during gestation preventing stone formation. We think that long time periods are needed for hypercalciuria to be able to lead to the formation of urinary calculi in pregnant women (except women having a positive family history). Therefore, we think that the pregnancy alone does not predispose to a suitable condition for calculi.