Amniotic fluid content in children with kidney and urinary tract anomalies determines pre- and postnatal development.

Background: Renal oligohydramnios (ROH) describes an abnormally low volume of amniotic fluid (AF) during pregnancy. ROH is mostly caused by congenital fetal kidney anomalies. The ROH diagnosis frequently implies an increased risk of peri- and postnatal fetal mortality and morbidity. The present study aimed to evaluate the impact of ROH on pre-and postnatal development in children with congenital kidney anomalies.

Methods: This retrospective study included 168 fetuses with anomalies in the kidney and urinary tract. Based on the amount of AF measured by ultrasound, patients were divided into three groups: normal amniotic fluid (NAF), amniotic fluid in the lower normal range (LAF), and ROH. These groups were compared with respect to prenatal sonographic parameters, perinatal outcomes, and postnatal outcomes.

Results: Among the 168 patients with congenital kidney anomalies, 26 (15%) had ROH, 132 (79%) had NAF, and 10 (6%) had LAF. Of the 26 families affected by ROH, 14 (54%) decided to terminate pregnancy. Of 10 live-born children in the ROH group, 6 (60%) survived the observation time; of these, 5/6 presented with chronic kidney disease, stages I-III, at their last examination. The main differences in postnatal development between the ROH group and the NAF and LAF groups were: restricted height and weight gain, respiratory issues, complicated feeding, and the presence of extrarenal malformations.

Conclusions: ROH is not a mandatory indicator of severe postnatal kidney function impairment. However, children with ROH have complicated peri-and postnatal periods, due to the presence of concomitant malformations, which must be considered in prenatal care. A higher resolution version of the Graphical abstract is available as Supplementary information.