, Susanne Hvolgaard Mikkelsen, PhD, of Aarhus (Denmark) University and her associates said.
“Caffeine metabolism is delayed during pregnancy, allowing longer opportunities for absorption. Caffeine increases dopamine levels by slowing down the rate of dopamine reabsorption, and this dysfunction of the dopaminergic system is thought to explain part of the association between caffeine consumption and offspring behavioral disorders,” the investigators said.
From 1996 to 2002, Danish physicians recruited women during their first pregnancy visit to participate in a study evaluating daily coffee and tea consumption during pregnancy, with follow-up of the children at age 11 years using the Danish National Birth Cohort. A follow-up questionnaire, including thewas completed by the children, their parents, and their teachers; the results were paired with data on coffee and tea consumption by the mothers of 47,491 children. At 15 weeks’ gestation, 12% of the women had consumed more than three cups/day of coffee, and 3% ingested eight or more cups/day of coffee; 19% of the women drank more than three cups/day of tea, and 4% drank eight or more cups/day of tea. The amount of coffee and tea consumed at 30 weeks’ gestation was only slightly less.
The percentage of children predicted to have “possible/probable” ADHD was 5%, conduct-oppositional disorders was 7%, anxiety-depressive disorders was 7%, and any psychiatric disorder was 14%.
A statistically significant association was found between maternal consumption of eight or more cups of coffee at 15 weeks’ gestation and greater risk of ADHD (a risk ratio [RR] of 1.47), conduct-oppositional disorder (RR, 1.22), and any psychiatric disorder (RR, 1.23). A statistically significant link was found between maternal consumption of eight or more cups of tea at 15 weeks’ gestation and greater risk of conduct-oppositional disorder (RR, 1.21). There was a statistically significant association between maternal consumption of eight or more cups of tea at 15 weeks’ gestation and a higher risk of anxiety-depressive disorder (RR, 1.28), but not for coffee. These significant relationships were not found again at 30 weeks’ gestation.
“The period of greatest prenatal brain development is 10-26 weeks after conception,which may explain our results suggesting the fetus to be more vulnerable to caffeine in first and second trimester, compared with the third trimester,” the researchers said.
There was no information available about caffeine consumption by chocolate, energy drinks, or medication; the measure of cola consumption also was not taken into account. Confounding by genetics or socioeconomic factors may affect these findings,and her associates said.
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