Comment on “Trends Over Time in Cognitive Outcomes of Children Born Very Preterm: A Systematic Review and Meta-Analysis”

Advances in perinatal care have improved the survival for children born very preterm (VPT; <32 wk of gestation). Compared with term-born children, VPT children have a greater risk of long-term developmental issues, such as cognitive impairment, cerebral palsy (CP), motor, socioemotional and psychiatric disorders, and sensory impairment. Cognitive function serves as a key outcome for examining development issues due to its close association with physical and mental well-being, academic attainment, socioeconomic outcomes, and life prospects. However, studies on long-term outcomes in VPT children have been mixed. While some studies have reported reduced rates of CP and hearing and vision loss, others have found that quality of life and neurodevelopmental, behavioral, and academic outcomes have not improved and may be worsening. Robust evidence to evaluate change over time also have been limited. The aim of this study was to investigate trends in long-term outcomes in VPT and term-born children over time. This study included cohort studies that investigated cognitive ability, measured by IQ, in VPT children versus term-born children. Included were 5 systematic reviews published before 2019, plus new studies up to June 2024, which were identified using the same search strategies as the previous systematic reviews. The primary analysis looked at a cohort of children between 4 and 7 years of age. The secondary included one study from each cohort with the longest follow-up. A total of 137 studies were included in this review, with 131 unique cohorts representing 25,746 children. The primary analysis included 61 cohorts, representing 13,842 children with assessments at 4 to 7 years of age (8847 born PT and 4995 born at term). VPT children had lower IQ scores than term-born children pooled standard mean difference (SMD), −0.88; 95% CI, −0.97 to −0.79; prediction interval (PI) −1.47 to −0.29 (τ 2 = 0.08). No differences in pooled SMD were observed between new and previously identified cohorts. In addition, there was no evidence of an association between median birth year and SMD in IQ scores was observed (β = −0.002; 95% CI, −0.012 to 0.008; P = 0.70; τ 2 = 0.10). No time trend was observed in linear and nonlinear models (β = 0.001; 95% CI, −0.005 to 0.007; P = 0.79; τ 2 = 0.06). In conclusion, VPT children had significantly lower IQ scores compared with term-born children, and this deficit has not decreased over time. (Summarized from Behboodi S, Chaimani A, Benhammou V, et al. Trends over time in cognitive outcomes of children born very preterm: A systematic review and meta-analysis. JAMA Pediatr 2025;179:1074-1081. doi: 10.1001/jamapediatrics.2025.2221).