High intelligence and intelligence profile discrepancies in preterm children: a systematic review and meta-analysis

Aim: To determine (Very) High Average and Extremely High intelligence and explore disharmonic intelligence profiles in preterm born children. Methods: For studies before 2017, three previous systematic reviews regarding intelligence in preterm born children were used. For studies after 2017, a search was conducted using Medline, PsychInfo and Embase. Studies reporting (index) intelligence quotient (IQ) scores of preterm versus term born children aged 5–18 years were included. Proportions of preterm versus term born children with (Very) High (≥1SD total IQ score) and Extremely High intelligence (≥2SD) with risk ratios (RR) and 95 % confidence interval (CI) were determined using random-effects model. Studies with ≥0.5 Standard Mean Difference between mean index IQ scores were classified as disharmonic. Results: We included 102 studies (13,773 preterm and 14,496 term born children). 11.6 % (95 % CI 0.11–0.12) of preterm children had (Very) High intelligence versus 26.6 % (95 % CI 0.26–0.27) of term children (RR 0.40, 95 % CI 0.36–0.45). Extremely High intelligence was reported in 1.9 % (95 % CI 0.016–0.021) versus 5.4 % (95 % CI 0.050–0.060) respectively (OR 0.30, 95 % CI: 0.24–0.38). 22 of 58 studies (37.9 %) indicated disharmonic profiles in preterm children. Conclusions: Approximately one in ten preterm born child has (Very) High average intelligence and they are prone to developing disharmonic intelligence profiles. This highlights the need for a multifaceted cognitive evaluation, including individual IQ index scores. Recognizing both cognitive strengths and weaknesses enables the development of tailored educational strategies to support the learning potential of preterm born children.