Background: Recent studies have suggested an association between prenatal paracetamol exposure and adverse neurodevelopmental outcomes in children. However, these findings may be confounded by unmeasured factors related to maternal use of paracetamol and child outcomes.Objective: To examine the association between duration and timing of prenatal paracetamol exposure on parent-reported communication skills, behaviour, and temperament in preschool-aged children, with focus on the role of unmeasured confounding. Methods:We used data from the Norwegian Mother and Child Cohort Study. Linear and generalised linear models with inverse probability weights and robust standard errors were used to quantify the association between prenatal paracetamol exposure and continuous and categorical outcomes. Results:Of the 32 934 children included in our study, 8374 (25.4%), 4961 (15.1%), and 1791 (5.4%) were prenatally exposed to paracetamol in one, two, and three trimesters, respectively.Children exposed to paracetamol in two trimesters scored lower on shyness compared with unexposed children (β −0.62, 95% confidence interval [CI] −1.05, −0.19). Children exposed to paracetamol in three trimesters had a moderate increased risk of internalising behaviour problems (relative risk (RR) 1.36, 95% CI 1.02, 1.80) and borderline externalising behaviour problems (RR 1.22, 95% CI 0.93, 1.60) compared with unexposed children. Children exposed to paracetamol in 2nd/3rd trimester scored lower on shyness (β −0.32, 95% CI −0.66, 0.02) compared with unexposed children. Sensitivity analyses indicated that unmeasured confounders play an important role and may potentially bias the effect estimates away from the null. Conclusions:Timing of exposure and short-term use of paracetamol during pregnancy do not seem to pose any substantial risk of the outcomes examined. Although we found an association between paracetamol use in multiple trimesters and lower shyness and greater internalising behaviour in preschool-aged children, we cannot rule out chance or unmeasured confounding as possible explanations for these findings. K E Y W O R D Schild neurodevelopment, MoBa, paracetamol, pregnancy This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

PurposeThe present study describes the safety profile of medications used during pregnancy across European countries and examines maternal factors associated with the use of risky medications during pregnancy.MethodsThis study is based on a multinational, web‐based study conducted in 15 European countries from October 2011 to February 2012. Information about maternal demographics, illnesses, and medication use during pregnancy was collected via an electronic questionnaire. Pregnant women and new mothers with a child less than 1‐year‐old could participate. The Swedish, Australian, and U.S. risk classification systems were used to evaluate medication safety. Descriptive statistics and generalized estimating equation models were used.ResultsA total of 587 medications were reported by the study sample (n = 6657). Sixty‐nine percent of the women used medications classified as safe, 28% used medications classified as risky, and 3% used medications with no classification available. Both socio‐demographic and medical factors were associated with the use of risky medications during pregnancy. Having a chronic disorder was the factor with the strongest association with the use of risky medications during pregnancy (adjusted odds ratio = 3.99, 95% confidence interval 3.54–4.49).ConclusionsThe majority of women used medications classified as safe to use during pregnancy. However, a considerable proportion of women still used medications classified as risky. Having a chronic disorder was an important driver for using risky medications. Such use may still be appropriate when considering the woman's underlying condition. Pre‐pregnancy counselling is important to ensure safe medication use for both mother and child. © 2017 The Authors. Pharmacoepidemiology & Drug Safety Published by John Wiley & Sons Ltd.

Key Points Question Is prenatal analgesic opioid exposure associated with attention-deficit/hyperactivity disorder (ADHD) in children? Findings In this cohort study of 73 480 children, with a mean follow-up of 11 years, no association between timing of analgesic opioid exposure during pregnancy and ADHD was found. The risk of ADHD diagnosis was elevated after exposure to opioids for 5 or more weeks compared with exposure for 4 weeks or less. Meaning The increased risk of ADHD observed in this study may be driven by longer duration of exposure; however, the role of residual or unmeasured confounding cannot be excluded, and this finding requires further study.

No abstract