Does the individualized reference outperform a simple ultrasound-based reference applied to birth weight in predicting child neurodevelopment?

Small for gestational age-cognitive performance from infancy to adulthood: an observational study

OBJECTIVE

To determine whether cognitive performance from infancy to adulthood is affected by being born small for gestational age (SGA), and if this depends on the SGA reference used. Furthermore, to determine SGA's effect while considering the effects of very preterm/very low birthweight (VP/VLBW), socio-economic status (SES) and parent-infant relationship.

DESIGN, SETTING AND POPULATION

A total of 414 participants (197 term-born, 217 VP/VLBW) of the Bavarian Longitudinal Study.

METHODS

Small for gestational age was classified using neonatal or fetal growth references. SES and the parent-infant relationship were assessed before the infant was 5 months old.

MAIN OUTCOME MEASURES

Developmental (DQ) and intelligence (IQ) tests assessed cognitive performance on six occasions, from 5 months to 26 years of age.

RESULTS

The fetal reference classified more infants as SGA (<10th centile) than the neonatal reference (n = 138, 33% versus n = 75, 18%). Using linear mixed models, SGA was associated with IQ -8 points lower than appropriate for gestational age, regardless of reference used (95% CI -13.66 to -0.64 and 95% CI -13.75 to -1.98). This difference narrowed minimally into adulthood. Being VP/VLBW was associated with IQ -16 (95% CI -21.01 to -10.04) points lower than term-born participants. Low SES was associated with IQ -14 (95% CI -18.55 to -9.06) points lower than high SES. A poor parent-infant relationship was associated with IQ -10 points lower than those with a good relationship (95% CI -13.91 to -6.47).

CONCLUSIONS

Small for gestational age is associated with lower IQ throughout development, independent of VP/VLBW birth, low SES or poor parent-child relationship. Social factors effects on IQ comparable to those of SGA and should be considered for interventions.

TWEETABLE ABSTRACT

Small for gestational age is associated with lower cognitive performance from infancy to adulthood.

The influence of fetal growth reference standards on assessment of cognitive and academic outcomes of very preterm children

OBJECTIVE

To compare 3 methods of identifying small-for-gestational-age (SGA) status in very preterm children as related to cognitive function and academic outcome.

STUDY DESIGN

There were 1038 singletons in the Epipage Study, born before 33 weeks in 1997 without severe neurosensory impairment, who were classified as SGA when birth weight was below the 10th percentile according to: (1) birth weight (bw) reference: SGA(bw)/appropriate for gestational age (AGA)(bw); (2) intrauterine (intraut) reference: SGA(intraut)/AGA(intraut); and (3) intrauterine reference customized (cust) according to individual characteristics: SGA(cust)/AGA(cust). Cognitive function was assessed by the mental processing composite (MPC) score of the Kaufman Assessment Battery for Children at age 5 and academic achievement by a parental questionnaire at age 8.

RESULTS

Of the children, 15% were SGA(bw), 38% were SGA(intraut), and 39% were SGA(cust). All children SGA(bw) were also SGA(intraut) and SGA(cust). MPC was <85 in 32% of children and 27% had low academic achievement. AGA(bw)/SGA(intraut) children had a significantly increased risk of MPC <85 (adjusted OR 1.74, 95% CI 1.22-2.28) or low academic achievement (adjusted OR 1.64, 95% CI 1.05-2.55) compared with AGA(bw)/AGA(intraut) children. The SGA(cust) group was only slightly different from the SGA(intraut) group.

CONCLUSIONS

An intrauterine reference identified very preterm infants at risk of poor cognitive or academic outcomes better than a birth weight reference. Customization resulted in only slight modifications of the SGA group.