# Association between birthweight discordance and extrauterine growth restriction among preterm twins: a national multi-center study in China

## TL;DR

This study found that greater birthweight differences in preterm twins are linked to a higher risk of poor growth after birth, especially in twins who were already small for their gestational age.

## Contribution

The study identifies birthweight discordance as a significant risk factor for EUGR in preterm twins, with a specific focus on the modifying role of SGA.

## Key findings

- BWD >25% was associated with a 1.59-fold increased risk of EUGR compared to BWD ≤15%.
- The association between BWD and EUGR was stronger in SGA infants, with an adjusted OR of 1.38.
- The study suggests tailored NICU interventions may help reduce growth disparities in preterm twins.

## Abstract

This multicenter study investigated the association between birthweight discordance (BWD) and extrauterine growth restriction (EUGR) in preterm twins, and evaluated the modifying role of small for gestational age (SGA).

Data from 2,496 infants (1,248 twin pairs) admitted to 22 Chinese NICUs (2018–2020) were analyzed. BWD was calculated as the percentage difference in birthweight between larger and smaller twins, categorized into four groups (≤15%, 15%–20%, 20%–25%, >25%). EUGR was defined as discharge weight below the 10th percentile for corrected gestational age and sex (Fenton's chart). A generalized linear mixed model was employed to analyze the association between BWD and EUGR. Modification analysis was performed to assess the effect of SGA on this association.

BWD of >25% was associated with a significantly increased risk of EUGR compared to BWD ≤15% (adjusted OR = 1.59, 95% CI: 1.05–2.41). Stratified analysis revealed a consistent association in SGA infants (OR = 1.38, 95% CI: 1.30–1.47).

Findings highlight BWD as a critical risk factor for EUGR, particularly in SGA twins. This association suggests that future research should investigate whether tailored monitoring and nutritional interventions in NICUs could help mitigate these growth disparities.