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Keywords:

  • Prenatal Alcohol Exposure;
  • IQ;
  • Maternal Age;
  • MAST;
  • Moderator Variables and Effect Modification

Background: In contrast to the extensive literature documenting IQ deficits in patients with fetal alcohol syndrome, effects on IQ have not generally been reported for children with alcohol-related neurodevelopmental disorder (ARND). This study examined the role of maternal age, MAST, and quality of parenting in moderating the effects of prenatal alcohol exposure on the WISC-III IQ test in moderate-to-heavily exposed children.

Methods: A total of 337 inner-city African American children whose mothers were recruited prenatally were administered the WISC-III at 7.5 years. Alcohol exposure was assesed with a timeline follow-back interview administered at every prenatal clinic visit. Moderating effects of the three risk factors were examined by adding interaction terms to regression analyses and dichotomizing the moderators and performing separate regressions on the two groups.

Results: Prenatal alcohol exposure was related to WISC-III Freedom from Distractibility but not to Full Scale IQ for the sample as a whole. However, among children born to older mothers, an alcohol effect emerged on Full Scale IQ and five of seven composite IQ scores. Similarly, adverse effects were seen among children of MAST-positive mothers and children whose parents provided less optimal cognitive stimulation. Each additional ounce of absolute alcohol consumed per day during pregnancy was associated with a 2.9-point decrease in Full Scale IQ and a 5.6-point decrement on Freedom from Distractibility.

Conclusions: This study is the first to demonstrate IQ effects among children with ARND born to older and MAST-positive mothers, particularly in relation to first-trimester drinking. These findings suggest that there are subgroups of more vulnerable and severely affected children whose intellectual performance is compromised. A moderate- to heavy-drinking mother who has given birth to an unaffected child when she was younger needs to be warned that her risk of having an adversely affected child increases as she grows older.