Isabel Santos Silva

Weight discordance is a known risk factor for poor perinatal and neonatal outcomes. However, its impact on growth patterns during childhood remains unclear. This study aimed to examine how weight discordance influences the growth of weight, length, and head circumference during the first 36 months of corrected age (CA), according to chorionicity. A retrospective cohort study of monochorionic and dichorionic twin pairs with weight discordance, born between January 1, 2012, and December 31, 2021, in a tertiary maternity hospital. Weight discordance was considered if there was a difference of more than 20% in estimated fetal weight or birth weight between the twins. z-scores for weight, length, and head circumference at birth and at 1, 6, 12, 18, 24, and 36 months of CA were retrieved, and a longitudinal comparison was performed between monochorionic and dichorionic twin pairs. Two hundred thirty-two infants were included: 64 monochorionic and 168 dichorionic. In monochorionic twins, the differences in weight, length, and head circumference between the smaller and larger co-twins closed six months earlier than in dichorionic twins. Head circumference z-scores became similar six months earlier than length z-scores, and length z-scores became similar six months earlier than weight z-scores. Overall, both small and large monochorionic and dichorionic twins showed increases in all growth parameters during the first 36 months CA, with a more notable increase in smaller monochorionic twins. Conclusion: Inter-twin weight discordance was observed throughout the growth patterns of both larger and smaller twins. Smaller discordant twins showed adequate catch-up growth, leading to no differences in growth parameters compared to their larger co-twins by 36 months. This study highlights the role of chorionicity in the timing of resolution of growth disparities, with differences among dichorionic twins persisting longer. What Is Known: • Weight discordance is a known risk factor for poor perinatal and neonatal outcomes, but its effect on childhood growth patterns remains unclear. • Previous studies showed persistent weight and length discrepancies during early childhood, but there is limited data on head circumference and time of growth discrepancy resolution. What Is New: • Head circumference z-scores in smaller twins caught up more quickly than length and weight z-scores, suggesting different rates of catch-up growth in different growth parameters. • Growth differences between dichorionic discordant twins persist longer than in monochorionic twins, but by 36 months, no differences remained in any growth parameter.

Background: The association between fetal growth restriction (FGR) and childhood neurodevelopmental delay is unclear and the evidence available to the present date shows conflicting results. Our aim was to analyse the impact of early-onset FGR on the neurodevelopmental outcome at 24 months of corrected age in very preterm infants. Methods: Retrospective cohort study of very preterm infants (≤ 32 weeks’ gestation) admitted to a neonatal intensive care unit between 1 January 2013–31 December 2019. The control group comprised appropriate for gestational age (AGA) newborns. Griffiths III Mental Development Scale was performed at 24 months of corrected age. Results: 132 infants were included: 44 FGR and 88 AGA. Mean Global Development Quotient (GDQ) was lower for FGR infants (p = 0.004) even after adjusting for maternal and perinatal factors (β_adjusted -16.703; p = 0.009). The average scores for the neurodevelopmental domains were highest for personal-social-emotional skills (107.02 ± 16.34), followed by eye/hand coordination (105.61 ± 14.20) and foundation of learning skills (102.23 ± 13.74) and were lowest for gross motor (97.90 ± 11.88) and language/communication skills (96.39 ± 18.88). FGR had a significant negative impact on all domains except for gross motor skills. After adjustment, FGR continued to have a significant adverse impact on language/communication (β_adjusted -21.924; p = 0.013), eye/hand coordination (β_adjusted -15.446; p = 0.015) and foundation of learning skills (β_adjusted -15.211; p = 0.013). Conclusions: In very preterm infants, FGR was associated with a significantly increased risk of poor neurodevelopmental outcome at 24 months of corrected age compared to age-matched AGA infants.