Fullness of the calyces is usually transient and consequent to a full urinary bladder of the fetus. Occasionally, it can be a sign of obstruction of the outflow of the urinary bladder. It is important to measure the width of the dilated calyces, the anteroposterior diameter of the renal pelvis on either side, the width of the ureters if dilated and to check the urinary bladder after the fetus passes urine (for any residual urine). These should be compared after an interval of two weeks from the previous scan. Further decisions are to be based on these serial findings. If the findings remain the same then no follow up is required until 10-14 days after birth. Any increase in size would need close monitoring before and after delivery.