Defining postnatal growth failure among preterm infants in Indonesia

Background: Postnatal growth failure (PGF) frequently occurred among preterm infants with malnutrition. The decline in a weight-for-age z-score of ≥1.2 has been proposed to define PGF. It was unknown whether this indicator would be useful among Indonesian preterm infants. Methods: Infants of <37 weeks of gestational age born between 2020 and 2021, both stable and unstable, were recruited for a prospective cohort study during hospitalization in the level III neonatal intensive care unit at the Cipto Mangunkusumo General Hospital, Jakarta, Indonesia. The prevalence of PGF as defined by a weight-for-age z-score of <−1.28 (<10th percentile) at discharge, a weight-for-age z-score of <−1.5 (<7th percentile) at discharge, or a decline in a weight-for-age z-score of ≥1.2 from birth till discharge was compared. The association between those PGF indicators with the preterm subcategory and weight gain was assessed. The association between the decline in a weight-for-age z-score of ≥1.2 with the duration to achieve full oral feeding and the time spent for total parenteral nutrition was analyzed. Results: Data were collected from 650 preterm infants who survived and were discharged from the hospital. The weight-for-age z-score of <−1.28 or <−1.5 was found in 307 (47.2%) and 270 (41.5%) subjects with PGF, respectively. However, both indicators did not identify any issue of weight gain among subjects with PGF, questioning their reliability in identifying malnourished preterm infants. By contrast, the decline in a weight-for-age z-score of ≥1.2 was found in 51 (7.8%) subjects with PGF, in which this indicator revealed that subjects with PGF had an issue of weight gain. Next, a history of invasive ventilation was identified as a risk factor for preterm infants to contract PGF. Finally, the decline in a weight-for-age z-score of ≥1.2 confirmed that preterm infants with PGF took a longer time to be fully orally fed and a longer duration for total parenteral nutrition than the ones without PGF. Conclusion: The decline in a weight-for-age z-score of ≥1.2 was useful to identify preterm infants with PGF within our cohort. This could reassure pediatricians in Indonesia to use this new indicator.