Prolonged renal function impairment in infants born during the peri-viable period: A retrospective longitudinal cohort study

Abstract

Background: The number of infants born during the peri-viable period who survive has been increasing.

Aim: To clarify renal function in infants from the time of birth during the peri-viable period until their due date.

Study design: This retrospective cohort study was conducted at a single center.

Subjects: We reviewed the data of infants born at ≤28 weeks of gestation between 2018 and 2022 at our hospital. The infants were divided into the following groups: born at 22-24 weeks vs. 25-28 weeks (appropriate-for-gestational age [AGA] infants), and AGA infants vs. small-for-gestational age (SGA) infants (born at 22-28 weeks).

Outcome measures: We compared the perinatal data and renal function of the infants from birth until their due date.

Results: Eighty-one infants were included. Their serum creatinine, fractional excretion of sodium, and urine glucose levels were high or positive soon after birth but gradually improved. The urine albumin level was significantly higher among AGA infants born at 22-24 weeks, even at term equivalent age, than among those born at 25-28 weeks.

Conclusions: Persistent renal insufficiency was observed even around the term equivalent age in peri-viable infants. Follow-up data collected after the neonatal period should be investigated in these infants.

Keywords: Chronic kidney disease; Developmental Origins of Health and Disease; Extremely preterm infant; Glomerulus; Small-for-gestational age; Tubule.