In utero exposure to coumarins and cognition at 8 to 14 years old

Objective. To assess the cognitive abilities in school-aged children who ha ve been exposed to coumarins in utero. Background. Coumarin derivatives are an effective option for anticoagulant therapy in pregnant women. However, case reports describe anomalies of the fetal central nervous system after in utero exposure to coumarins. It is un clear whether prenatal exposure has an effect on cognitive functioning late r in childhood. Methods. The exposed cohort consisted of 291 children from mothers who were prospectively registered because of coumarin treatment during pregnancy. T he nonexposed cohort included 253 age-matched peers. An IQ was estimated us ing subtests of the Weschler Intelligence Scale for Children-Revised. Educa tional achievement was examined with tests for reading, spelling, and arith metic. In addition, schoolteachers were asked to judge performance on langu age and arithmetic. The observers were not aware of the exposure status of the child. Results. No differences in mean IQ were found between the exposed and nonex posed cohort (mean difference: -1.1; 95% confidence interval [CI]: -3.2-1.1 ), but an IQ score below 80 was found in 11 children in the exposed compare d with 3 children in the nonexposed cohort (odds ratio [OR] = 3.1; CI: 0.8- 11.6). Regarding the tests for educational achievement, exposed children as a group performed as well as nonexposed controls. Exposed boys, in compari son with nonexposed boys, showed a higher frequency of poor performance on reading (OR = 2.9; CI: 1.1-7.4) and spelling (OR = 2.5; CI: 1.0-6.0). Conclusion. Cognitive functioning in coumarin-exposed children does not dif fer from nonexposed controls, but a minority of children seem to be prone t o the potential negative effects of coumarins during pregnancy.