What is the role of calyceal and ureteral dilation in the pathogenesis of urinary tract infection (UTI) during pregnancy?
Calyceal and ureteral dilatation are more common on the right side; in 86% of cases, the dilatation is localized to the right.
The degree of calyceal dilatation is also more pronounced on the right than the left (average 15 mm vs 5 mm).
This dilatation appears to begin by about 10 weeks’ gestation and worsens throughout pregnancy.
This is underscored by the distribution of cases of pyelonephritis during pregnancy: 2% during the first trimester, 52% during the second trimester, and 46% in the third trimester.