Socioeconomic disparities in the postnatal growth of preterm infants: a systematic review.

OBJECTIVE

To determine the effect of parental socioeconomic status (SES) on the postnatal growth of preterm infants.

METHODS

A systematic review (PROSPERO registration CRD42020225714) of original articles from Medline, Embase, CINAHL Plus and Web of Science published 1946-2023 was undertaken. Studies were included if they reported anthropometric growth outcomes for preterm infants according to parental SES. Data extraction and assessments of bias and health equity impact were conducted using custom-designed forms.

RESULTS

A narrative synthesis of twelve included studies was performed. Most infants were moderate to late preterm. The settings, growth outcomes, timings of growth measurement, and SES measures were heterogenous. Six studies demonstrated an adverse effect of low parental SES on the extrauterine growth of preterm infants, five studies showed no effect, and one study showed a potentially beneficial effect. All studies had a high risk of bias, especially confounding and selection bias. The health equity impact of included studies was largely negative.

CONCLUSION

Limited and low-quality evidence suggests that socioeconomic minoritisation may adversely impact the growth of preterm infants, thereby widening existing socioeconomic health inequities. Observational studies informed by theorisation of the mechanistic pathways linking socioeconomic minoritisation to adverse postnatal growth are required to identify targets for intervention.

IMPACT

Limited evidence suggests low parental socioeconomic status (SES) adversely affects the postnatal growth of preterm infants across different settings. Early growth of preterm infants predicts neurodevelopmental outcomes and the risk of cardiovascular and metabolic disease in adulthood. Systematic screening of over 15,000 articles identified only twelve studies which reported postnatal growth outcomes for preterm infants according to parental SES. The health equity impact of the included studies was systematically assessed, and found to be negative overall. This study highlights limitations in existing evidence on the association between parental SES and postnatal growth, and delineates avenues for future research.