Background: Animal studies have shown that prenatal stress is linked with altered laterality in the offspring.
Aims: The aim of this study was to test the hypothesis that antenatal maternal anxiety was associated with altered lateralisation in children, as demonstrated by mixed handedness.
Study design and subjects: We used the Avon Longitudinal Study of Parents and Children (ALSPAC), a prospective longitudinal study that has followed women since pregnancy. The final analysis included data on 7431 mother-child pairs. Maternal anxiety was measured at 18- and 32-week gestation and 8 weeks postnatally using a self-report inventory. Child handedness was assessed at 42 months using an established maternal report scale. Information on maternal and paternal handedness, as well as data on possible confounding variables such as obstetric and antenatal risks, were also assessed.
Results: Univariable analysis showed that antenatal anxiety at 18 weeks was associated with mixed-handedness in the child, OR=1.28 (95% CI 1.09-1.50, p<0.01). Although boys were more likely than girls to be mixed handed, the link with antenatal anxiety was similar. There was no significant association with antenatal anxiety at 32 weeks. Multivariable analyses indicated that maternal anxiety at 18 weeks of pregnancy predicted an increased likelihood of mixed-handedness in the child (OR=1.23, 95% CI 1.02-1.48, p<0.05), independently of parental handedness, obstetric and other antenatal risks, and postnatal anxiety.
Conclusion: This result provides further evidence for a link between antenatal anxiety and fetal programming in humans.