Study of 64 322 live-born children and mothers enrolled in the Danish National Birth Cohort during 1996-2002 found a strong correlation between acetaminophen (found in common painkillers like Tylenol) use among pregnant women and the rate of attention-deficit/hyperactivity disorder (ADHD) diagnoses, prescriptions for ADHD medications, or having ADHD-like behaviors at age 7 years. More than half of all mothers reported acetaminophen use while pregnant and exposure response trends were found with increasing frequency of acetaminophen use during gestation for all outcomes. Because the exposure and outcome are frequent, these results are of public health relevance but further investigations are needed.丹麦对在1996-2002年间纳入全国出生群组的64322名活产儿童和母亲的研究发现， 孕期使用乙酰氨基酚（扑热息痛，常用止痛药如泰诺的成分）与儿童多动症的诊断，多动症药物处方以及7岁时有多动症行为的比率之间有很强的相关性。一半以上的母亲报告曾在孕期用过乙酰氨基酚，而且有趋势表明乙酰氨基酚的使用率越高则上述不良反应也越多。由于乙酰氨基酚的使用率和上述不良反应的发生率都很高，该报告对公众健康有重大意义，但还需要进一步研究。
