History of Small for Gestational Age at Birth With Verbal and Non-verbal Intelligence: A Case-Control Study Among Preschool Children

OBJECTIVE: Advances in technology and treatments have improved the survival rate of small for gestational age (SGA) infants that need more concern for their neurodevelopmental outcomes. In the present study, we hypothesized that a history of SGA may affect verbal and non-verbal intelligence indices among pre-school children. MATERIALS AND METHODS: A case-control study was conducted at the Tehran University of Medical Sciences (Tehran-Iran, 2020). Totally 232 children entered the study. An expert pediatrician examined all included subjects. Based on birth weight (extracted from medical records), participants were divided into the case (born SGA) and control (born Appropriate for gestational age (AGA)) groups. Wechsler Intelligence Scale (WISC) and Conners tests were implemented to assess intelligence quotient (IQ), verbal, attention, development, and executive functions. Finally, total scores were compared between groups. RESULTS: Totally, 232 preschool children were included in the study. Of all, 114 (49.1%) and 118 (50.9%) subjects had the history of born SGA and AGA, respectively. The results related to WISC scores showed that the mean WISC-verbal score among children born SGA was significantly higher than children born AGA; (114.288±18.130 vs. 108.898±20.145; P=0.024). This significant difference was associated with Vocabulary (13.531±2.843 vs. 12.745±3.242; p=0.046) and Similarities (14.054±3.630 vs. 13.279±4.898; p=0.048) domains between the groups. The results related to different domains of the Conners test also showed that the mean scores of Inattention (B) and attention deficit hyperactive disorder score (D) in the case group were higher than these scores in the control group; however, these differences were not significant (4.929±3.511 vs. 4.906±4.300; p=0.495 &10.371±5.867 vs. 10.093±7.588; p=0.211). CONCLUSION: Our results indicated that the development of non-verbal intelligence in children born with SGA had been delayed. This finding shows that these children may need more consideration during the preschool period and after that.