Evaluation and management of isolated renal pelviectasis diagnosed on second-trimester ultrasound

A 32-year-old gravida 1 para 0 presents for a routine ultrasound at 21 weeks' gestation. Ultrasound examination demonstrates unilateral pelviectasis (Figure 1). What is the definition of fetal pelviectasis and how frequently is it present during midtrimester?

A. Fetal pelviectasis (also called pyelectasis or renal pelvis dilation) is a common finding on midtrimester ultrasound, occurring in 0.5% to 4.5% of fetuses.1-3 It can be unilateral or bilateral, and is more common in male fetuses. Carbone and colleagues recently reported the frequency of fetal pelviectasis in 62,103 women undergoing midtrimester ultrasound.2 There were 1,248 cases of pelviectasis (2% incidence) and in 84.5% of these cases (n=1,055) it was an isolated finding.

What other ultrasound findings are important to assess?