Frequency of postnatal hydronephrosis in infants with a renal anterior–posterior pelvic diameter > 4 mm on midtrimester ultrasound

Abstract

Objective: To examine the association of antenatal renal pelvic dilatation observed on midtrimester ultrasound screening with the presence of hydronephrosis in newborn infants. Materials and methods: The records of patients who received fetal ultrasound examination at 18–28 weeks' gestation from May 2008 to March 2012 were retrospectively reviewed. A fetal renal pelvic anterior–posterior (AP) diameter > 4 mm was considered abnormal and ≤ 4 mm was considered normal. On postnatal ultrasound, a renal pelvic AP diameter > 3 mm was considered to indicate hydronephrosis and ≤ 3 mm was considered normal. The association of postnatal hydronephrosis with prenatal pelvic AP diameter was determined using binary logistic regression analysis. Results: The study comprised 1310 newborn infants: 684 (52.2%) male and 626 (47.8%) female. Multivariate analysis showed a right or left prenatal AP renal pelvic diameter > 4 mm was associated with a higher risk of postnatal hydronephrosis compared with a right and left prenatal AP renal pelvic diameter ≤ 4 mm. Boys had a higher risk for postnatal hydronephrosis than girls (odds ratio = 2.42, p 4 mm on midtrimester ultrasound is predictive of postnatal hydronephrosis.

Keywords

• antenatal diagnosis
• fetal hydronephrosis
• renal pelvic diameter
• ultrasound