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Gestational diabetes hinders language development in early, middle childhood, study says

Wednesday, January 14 2009 | Comments

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What's This? Infants born to mothers with gestational diabetes may be more likely to experience language impairment in early and middle childhood, a new study suggests.

Researchers conducted a case-control, longitudinal study to compare infants of mothers with gestational diabetes to infants of mothers without gestational diabetes, looking specifically at language outcomes from ages 18 months to 7 years. The study included 2 birth cohorts--singletons from the Quebec Longitudinal Study of Child Development (n=1,835) and twins from the Quebec Newborn Twin Study (QNTS; n=998). Cases included 221 infants of mothers with gestational diabetes (105 singletons and 116 twins) and the remaining infants (1,730 singletons and 882 twins) served as controls.

The outcome measures were scores on the McArthur Communicative Development Inventory expressive and receptive vocabulary and grammar at ages 18 months and 30 months, the Peabody Picture Vocabulary Test receptive vocabulary at age 48 months and expressive and receptive vocabulary at age 60 months, and the Early Development Instrument (EDI) teacher-assessed communication at ages 72 months and 84 months (kindergarten and first grade).

Analyses of data revealed that gestational diabetes had a negative effect on expressive language at ages 18 months, 30 months, 72 months, and 84 months after adjusting for sex, socioeconomic status, and perinatal factors. Infants of mothers with diabetes scored 0.27 to 0.41 SD lower than control children on expressive vocabulary and expressive grammar at ages 18 months and 30 months, a difference that translated into a 4- to 12-word difference in vocabulary on a scale of 77 words (mean, 18 words) at age 18 months and a difference of up to 10 words on a scale of 100 words (mean, 62 words) at age 30 months.

In addition, controls were more advanced in their use of grammar, with 87% using word combinations often by age 30 months compared with 74% of the infants of mothers with diabetes.

There were no differences noted at ages 42 months and 60 months with respect to expressive and receptive vocabulary, but at 72/84 months, case infants scored 0.35 SD lower than controls on the EDI Oral Communication Scale (QNTS cohort).

Genetic modeling in the study provided preliminary evidence that genes may moderate the effect of gestational diabetes on expressive language, the researchers noted.

"Although the effect sizes for [gestational diabetes] are modest, they are second only to child gender, mother's education, and family income," the authors concluded.

They added, "The fact that expressive language is specifically affected is noteworthy given previous, documented motor delays in [infants of mothers with gestational diabetes]." (Dionne G, et al. Pediatrics 2008;122:e1073-e1079.)

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