Association of Acetaminophen Use During Pregnancy With Behavioral Problems in Childhood: Evidence Against Confounding

Neurodevelopmental outcomes following paracetamol use for treatment of patent ductus arteriosus: A review

AIM

Concerns exist regarding potential adverse neurodevelopmental outcomes associated with paracetamol exposure during pregnancy and early infancy. This review evaluates the evidence for the impact of paracetamol use for patent ductus arteriosus (PDA) treatment on neurodevelopmental outcomes in preterm infants.

METHODS

A literature search was performed via Medline, Ovid Embase and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases. The search details are below: ('Infant, Newborn' [MeSH] OR 'neonate*' [Title/Abstract]) AND ('Paracetamol' [MeSH] OR 'Acetaminophen' [Title/Abstract]) AND ('Ductus Arteriosus, Patent/drug therapy' [MeSH] OR 'patent ductus arteriosus' [Title/Abstract]) AND ('Neurodevelopmental Disorders' [MeSH] OR 'neurodevelopment*' [Title/Abstract] OR 'Child Development' [MeSH] OR 'Developmental Disabilities' [MeSH]). All studies were critically appraised and synthesised.

RESULTS

Seven studies reported neurodevelopmental outcomes after paracetamol use for PDA treatment in preterm infants <32 weeks gestation. The studies varied in dosage, route, and duration of paracetamol administration and in the methods used to assess neurodevelopmental outcomes. None of the studies revealed different outcomes between paracetamol-exposed preterm infants and controls.

CONCLUSION

Current low-to-moderate quality evidence suggests no association between paracetamol used for PDA treatment and adverse neurodevelopmental outcomes in preterm infants. Future well-powered studies with standardised neurodevelopmental assessments are warranted to strengthen the current evidence base.

Postnatal acetaminophen exposure and neurodevelopmental outcomes at 18-21 months corrected gestational age in preterm infants <29 weeks gestation: a retrospective cohort study

BACKGROUND

Studies have reported prenatal acetaminophen exposure is associated with abnormal neurodevelopment. There is limited and conflicting data on neurodevelopmental outcomes following postnatal acetaminophen exposure. Our objective was to investigate the neurodevelopmental outcomes of preterm infants < 29 weeks gestation postnatally exposed to acetaminophen.

METHODS

Retrospective cohort study of infants born between 2008 and 2017 at a tertiary care perinatal center. Exclusion criteria included chromosomal disorders, major congenital abnormalities, and congenital infections. The primary outcome was a composite score of <85 on the cognitive, language, or motor components of the Bayley Scales of Infant and Toddler Development, 3rd edition, assessed at 18 to 21 months corrected gestational age. Multivariate logistic regression was used to assess confounders.

RESULTS

Of the 945 infants included in the study, 120 were in the acetaminophen group. There was no difference in any of Bayley-III cognitive, language or motor composite scores of < 85 between the two groups for postnatal acetaminophen exposure, adjusted odds ratios (aORs) 1.03, 95% CI 0.60-1.78, or days of acetaminophen use, aORs 1.10, 95% CI 0.93-1.29.

CONCLUSIONS

There was no difference in neurodevelopmental outcome between the acetaminophen exposed and non-exposed groups. Our results need validation in larger cohorts.

IMPACT

Animal research and cohort studies have suggested that prenatal acetaminophen exposure may be associated with an elevated risk of neurobehavioral abnormalities. However, there is limited and conflicting research on the impact of postnatal acetaminophen on neurodevelopment. The results of this study suggest that postnatal acetaminophen does not negatively impact neurodevelopment at 18 to 21 months in preterm infants born at <29 weeks gestational age. While these results need validation in larger and more longitudinal studies, this study provides reassurance for the use of postnatal acetaminophen in extremely preterm infants.

Examining the relationship of acetaminophen use during pregnancy with early language development in children

BACKGROUND

Acetaminophen is the only analgesic considered safe for use throughout pregnancy. Recent studies suggest that use during pregnancy may be associated with poorer neurodevelopmental outcomes in children, but few have examined language development.

METHODS

The Illinois Kids Development Study is a prospective birth cohort in east-central Illinois. Between December 2013 and March 2020, 532 newborns were enrolled and had exposure data available. Participants reported the number of times they took acetaminophen six times across pregnancy. Language data were collected at 26.5-28.5 months using the MacArthur-Bates Communicative Development Inventories (CDI; n = 298), and 36-38 months using the Speech and Language Assessment Scale (SLAS; n = 254).

RESULTS

Taking more acetaminophen during the second or third trimester was associated with marginally smaller vocabularies and shorter utterance length (M3L) at 26.5-28.5 months. More acetaminophen use during the third trimester was also associated with increased odds of M3L scores ≤25th percentile in male children. More use during the second or third trimester was associated with lower SLAS scores at 36-38 months. Third trimester use was specifically related to lower SLAS scores in male children.

CONCLUSIONS

Higher prenatal acetaminophen use during pregnancy may be associated with poorer early language development.

IMPACT

Taking more acetaminophen during pregnancy, particularly during the second and third trimesters, was associated with poorer scores on measures of language development when children were 26.5-28.5 and 36-38 months of age. Only male children had lower scores in analyses stratified by child sex. To our knowledge, this is the first study that has used a standardized measure of language development to assess the potential impact of prenatal exposure to acetaminophen on language development. This study adds to the growing body of literature suggesting that the potential impact of acetaminophen use during pregnancy on fetal neurodevelopment should be carefully evaluated.

Prevalence of self-medication practices among pregnant women in India: A systematic review and meta-analysis

BACKGROUND

Self-medication practice among pregnant women is a global concern. However, its understanding in the Indian context is limited due to a lack of comprehensive studies.

PURPOSE

This study aimed to comprehensively assess the prevalence of self-medication, the medications used for self-medication, diseases/conditions associated with self-medication, and the reasons for self-medication among Indian pregnant women.

METHODS

This study was carried out following the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A thorough search was done in PubMed, Embase, and Google Scholar to find articles that were published up until May 2023. Inclusion criteria comprised observational studies reporting self-medication prevalence among pregnant women in India. Data were extracted using a standardized sheet, and a random-effects model was applied to determine the overall prevalence of self-medication using R software. The I2 statistic was employed to assess the heterogeneity among the studies.

RESULTS

This study analyzed eight studies with a collective sample size of 2208 pregnant women. The pooled prevalence of self-medication among pregnant Indian women was 19.3% (95% CI: 7.5%-41.3%; I2 = 99%; p < 0.01). Common self-treated conditions were cold, cough, fever, headache, and stomach disorders. Antipyretics, analgesics, antihistamines, and antacids were frequently used for self-medication. The perception of mild ailment, immediate alleviation, convenience, time savings, and advice from family, friends, or the media were all reasons for self-medication. Local pharmacies were the most usual source for obtaining drugs, and pharmacists, family, friends, and past prescriptions were common sources of medicine information.

CONCLUSIONS

A low yet substantial number of pregnant women in India are engaged in self-medication practices. Appropriate strategies need to be planned to reduce self-medication practices to attain sustainable developmental goals for maternal health in India.

Acetaminophen causes neurodevelopmental injury in susceptible babies and children: no valid rationale for controversy

Despite the worldwide acceptance of acetaminophen (APAP) as a necessary medicine in pediatrics, evidence that early exposure to APAP causes neurodevelopmental injury in susceptible babies and children has been mounting for over a decade. The evidence is diverse and includes extensive work with laboratory animals, otherwise unexplained associations, factors associated with APAP metabolism, and limited studies in humans. Although the evidence has reached an overwhelming level and was recently reviewed in detail, controversy persists. This narrative review evaluates some of that controversy. Evidence from the pre- and postpartum periods was considered to avoid controversy raised by consideration of only limited evidence of risks during the prepartum period. Among other issues, the association between APAP use and the prevalence of neurodevelopmental disorders was considered. A systematic review revealed that the use of APAP in the pediatric population was never tracked carefully; however, historical events that affected its use were documented and are sufficient to establish apparent correlations with changes in the prevalence of neurodevelopmental disorders. Moreover, problems with the exclusive reliance on results of meta-analyses of large datasets with limited time frames of drug exposure were reviewed. Furthermore, the evidence of why some children are susceptible to APAPinduced neurodevelopmental injuries was examined. We concluded that available evidence demonstrates that early exposure to APAP causes neurodevelopmental injury in susceptible babies and small children.

Inhibitory Effect of Acetaminophen on Ocular Pigmentation and its Relationship with Thyroxine in Zebrafish Embryos

Acetaminophen (N-acetyl-p-aminophenol; APAP) is one of the most widely used analgesics. To examine the toxicity of APAP, we used zebrafish embryos as model animals to detect the effect of APAP on the thyroid system of zebrafish embryos. The zebrafish embryos were exposed to APAP from 4 h post fertilization (4 hpf) until observation. The experimental results showed that APAP caused pericardial edema and decreased pigmentation in the zebrafish embryos or larvae. The APAP treatment caused a decrease in the expression of tpo and thrβ in the zebrafish at 36 and 72 hpf. The transcriptomic analysis found that APAP affected retinol metabolism, the metabolism of xenobiotics by cytochrome P450, and the tyrosine metabolism pathway. The harmful effect of APAP on zebrafish embryos might be due to its disrupting effect on the functional regulation of the thyroid hormone system.

The relationship of prenatal acetaminophen exposure and attention-related behavior in early childhood

Acetaminophen is currently the only analgesic considered safe for use throughout pregnancy, but recent studies indicate that prenatal exposure to acetaminophen may be related to poorer neurodevelopmental outcomes. Multiple studies have suggested that it may be associated with attention problems, but few have examined this association by trimester of exposure. The Illinois Kids Development Study is a prospective birth cohort located in east-central Illinois. Exposure data were collected between December 2013 and March 2020, and 535 newborns were enrolled during that period. Mothers reported the number of times they took acetaminophen at six time points across pregnancy. When children were 2, 3, and 4 years of age, caregivers completed the Child Behavior Checklist for ages 1.5-5 years (CBCL). Associations of acetaminophen use during pregnancy with scores on the Attention Problems and ADHD Problems syndrome scales, the Internalizing and Externalizing Behavior composite scales, and the Total Problems score were evaluated. Higher acetaminophen exposure during the second trimester of fetal development was associated with higher Attention Problems, ADHD Problems, Externalizing Behavior, and Total Problems scores at ages 2 and 3. Higher second trimester exposure was only associated with higher Externalizing Behavior and Total Problems scores at 4 years. Higher cumulative exposure across pregnancy was associated with higher Attention Problems and ADHD Problems scores at ages 2 and 3. Findings suggest that prenatal acetaminophen exposure, especially during the second trimester, may be related to problems with attention in early childhood.

The Dangers of Acetaminophen for Neurodevelopment Outweigh Scant Evidence for Long-Term Benefits

Based on available data that include approximately 20 lines of evidence from studies in laboratory animal models, observations in humans, correlations in time, and pharmacological/toxicological considerations, it has been concluded without reasonable doubt and with no evidence to the contrary that exposure of susceptible babies and children to acetaminophen (paracetamol) induces many, if not most, cases of autism spectrum disorder (ASD). However, the relative number of cases of ASD that might be induced by acetaminophen has not yet been estimated. Here, we examine a variety of evidence, including the acetaminophen-induced reduction of social awareness in adults, the prevalence of ASD through time, and crude estimates of the relative number of ASD cases induced by acetaminophen during various periods of neurodevelopment. We conclude that the very early postpartum period poses the greatest risk for acetaminophen-induced ASD, and that nearly ubiquitous use of acetaminophen during early development could conceivably be responsible for the induction in the vast majority, perhaps 90% or more, of all cases of ASD. Despite over a decade of accumulating evidence that acetaminophen is harmful for neurodevelopment, numerous studies demonstrate that acetaminophen is frequently administered to children in excess of currently approved amounts and under conditions in which it provides no benefit. Further, studies have failed to demonstrate long-term benefits of acetaminophen for the pediatric population, leaving no valid rationale for continued use of the drug in that population given its risks to neurodevelopment.

Multi-omics approach reveals dysregulated genes during hESCs neuronal differentiation exposure to paracetamol

Prenatal paracetamol exposure has been associated with neurodevelopmental outcomes in childhood. Pharmacoepigenetic studies show differences in cord blood DNA methylation between unexposed and paracetamol-exposed neonates, however, causality and impact of long-term prenatal paracetamol exposure on brain development remain unclear. Using a multi-omics approach, we investigated the effects of paracetamol on an in vitro model of early human neurodevelopment. We exposed human embryonic stem cells undergoing neuronal differentiation with paracetamol concentrations corresponding to maternal therapeutic doses. Single-cell RNA-seq and ATAC-seq integration identified paracetamol-induced chromatin opening changes linked to gene expression. Differentially methylated and/or expressed genes were involved in neurotransmission and cell fate determination trajectories. Some genes involved in neuronal injury and development-specific pathways, such as KCNE3, overlapped with differentially methylated genes previously identified in cord blood associated with prenatal paracetamol exposure. Our data suggest that paracetamol may play a causal role in impaired neurodevelopment.

Potential adverse actions of prenatal exposure of acetaminophen to offspring

Acetaminophen (APAP) is a widely used as analgesic and antipyretic drug. APAP is also added as an active ingredient in various medications to relieve pain and reduce fever. APAP has been widely used in pregnant women in the past decades because it is considered a relatively safe drug with recommended dose in different countries. However, an increasing number of epidemiological and experimental studies have shown that APAP exposure during pregnancy may increase the risk of inducing reproductive and neurobehavior dysfunctions, hepatotoxicity in offspring. This review aims to assess the potential effects of prenatal APAP exposure on offspring growth and development.

In utero acetaminophen exposure and child neurodevelopmental outcomes: Systematic review and meta-analysis

BACKGROUND

Acetaminophen is a frequently used analgesic for pain and fever. There have been reports of adverse neurodevelopmental outcomes associated with in utero acetaminophen exposure. However, it is unclear whether this association is related directly to acetaminophen use, or the reasons for use.

OBJECTIVES

To summarise the literature on the association between in utero acetaminophen exposure and child neurodevelopmental outcomes, and assess the extent to which the association is due to confounding by indication.

DATA SOURCES

OVID for Medline, Embase, and PsycINFO, and EBSCO for CINAHL, from inception to August 18, 2022.

STUDY SELECTION AND DATA EXTRACTION

We searched for peer-reviewed, English-language studies on in utero acetaminophen exposure and child neurodevelopmental outcomes. Data were extracted using a standardised form created a priori, and quality was assessed using the Systematic Assessment of Quality in Observational Research.

SYNTHESIS

We generated pooled risk ratios (RR) for outcomes examined by ≥3 studies using random-effects models; outcomes that could not be meta-analysed were narratively summarised following Synthesis Without Meta-Analysis guidelines.

RESULTS

Twenty-two studies including 23 cohorts were eligible (n = 367,775 total participants; median: 51.7% with acetaminophen exposure). Studies were primarily prospective cohort studies from Europe and the US, with attention deficit/hyperactivity disorder (ADHD) being the most common outcome. Quality assessments resulted in 13.6% of studies being classified as high, 59.1% as medium, 22.7% as low, and 4.5% as very low quality. In utero acetaminophen exposure was associated with an elevated risk of ADHD (unadjusted pooled RR 1.32, 95% confidence interval [CI] 1.20, 1.44; I²  = 47%, n = 7 studies), with little difference after adjusting for confounders, including indications for acetaminophen use (adjusted pooled RR 1.34, 95% CI 1.15, 1.55; I²  = 50%, n = 4 studies).

CONCLUSIONS

Confounding by indication did not explain the association between in utero acetaminophen exposure and child ADHD. Further, high-quality research is needed on this and other neurodevelopmental outcomes.

Discontinuation of methylphenidate after long-term exposure in nonhuman primates

Attention-deficit hyperactivity disorder (ADHD) is a common human neurobehavioral disorder that usually begins in early childhood. Methylphenidate (MPH) has been used extensively as a first-line medicine for the treatment of ADHD. Since ADHD is often diagnosed in early childhood and can persist for the entire lifespan, individuals may take MPH for many years. Given that in the course of one's lifetime a person may stop taking MPH for periods of time, or may implement lifestyle changes that may reduce the need for MPH entirely, it is important to understand how cessation of MPH affects the adult brain following long-term use of MPH. The blockage of the dopamine transporter (DAT) and the norepinephrine transporter (NET) by MPH may help with ADHD symptoms by boosting monoamine levels in the synapse. In the present study, microPET/CT was used to investigate possible neurochemical alterations in the cerebral dopamine system after cessation of long-term MPH administration in nonhuman primates. MicroPET/CT images were collected from adult male rhesus monkeys 6 months after they stopped receiving vehicle or MPH following 12 years of chronic treatment. The neurochemical status of brain dopaminergic systems was evaluated using the vesicular monoamine transporter 2 (VMAT2) ligand [¹⁸F]-AV-133 and a tracer for imaging dopamine subtype 2 (D₂) and serotonin subfamily 2 (5HT₂) receptors, [¹⁸F]-FESP. Each tracer was injected intravenously and ten minutes later microPET/CT images were obtained over 120 min. The binding potential (BP) of each tracer in the striatum was obtained using the Logan reference tissue model with the cerebellar cortex time activity curve (TAC) as an input function. Brain metabolism was also evaluated using microPET/CT images of [¹⁸F]-FDG. [¹⁸F]-FDG was injected intravenously, and ten minutes later, microPET/CT images were obtained over 120 min. Radiolabeled tracer accumulation in regions of interest (ROIs) in the prefrontal cortex, temporal cortex, striatum, and cerebellum were converted into standard uptake values (SUVs). Compared to the vehicle control group, the BPs of [¹⁸F] AV-133 and [¹⁸F]-FESP in the striatum were not significantly altered in MPH treated groups. Additionally, no significant differences were detected in the SUVs of [¹⁸F]-FDG in the MPH treated group compared with control. This study demonstrates that 6 months after cessation of long-term, chronic MPH treatment, there are no significant neurochemical or neural metabolic changes in the central nervous system (CNS) of non-human primates (NHPs) and suggests that microPET imaging is helpful in assessing the status of biomarkers of neurochemical processes linked to chronic CNS drug exposure. (Supported by NCTR).

Prenatal exposure to acetaminophen and adolescent assessment of behavior: Discrepancies by age and reporter

Acetaminophen, which is one of the most commonly used medications during pregnancy, has been linked to adverse neurodevelopmental outcomes among offspring during childhood. Less is known about associations with outcomes occurring later in adolescence. Methods: We conducted a follow-up study of children born between 1996 and 2002. Data on illnesses and medications, including acetaminophen, during pregnancy were collected through a standardized interview after delivery. Behavioral assessments were conducted at two subsequent time points, childhood (ages 5-10) and adolescence (ages 11-17). Outcomes examined included internalizing, externalizing, and total behavior problems based on the parent-completed Child Behavior Checklist (CBCL), the teacher-completed Teacher Report Form (TRF), and the youth-completed Youth Self Report (YSR, adolescent follow-up only). Adjusted linear regression models were used to calculate mean differences (MD) and 95% confidence intervals (95% CI) in T-scores comparing those with prenatal acetaminophen exposure to those without. Stabilized inverse probability weights were used to account for attrition. Results: Among the 216 mother-child dyads with completed parent and teacher behavioral assessments at both childhood and adolescence, prenatal acetaminophen exposure was not associated with behavioral problems according to either parent or teacher assessments. Modest increases in externalizing and total behavior problems were observed according to youth report (MD: 1.9). Compared to associations observed during the childhood follow-up, associations at adolescence were attenuated according to parent-report. Conclusion: Reported associations between prenatal acetaminophen exposure and behavioral outcomes were not consistent over time nor between reporters.

The safety of pediatric use of paracetamol (acetaminophen): a narrative review of direct and indirect evidence

Paracetamol (acetaminophen) use during pregnancy and early childhood was accepted as safe in the 1970s, but is now a subject of considerable concern. Careful analysis shows that initial acceptance of the drug was based on the false assumption that drug interactions in babies and adults are the same, and on a complete absence of knowledge regarding the impact of the drug on brain development. At least fourteen epidemiological studies now indicate that prenatal exposure to paracetamol is associated with neurodevelopmental problems. Based on these studies, it can be concluded that prenatal exposure to paracetamol causes statistically significant risks of developmental delays, attention deficit hyperactivity disorder, and a subtype of autism spectrum disorder (ASD) associated with hyperkinetic behavior. In contrast, data regarding postnatal exposure to paracetamol are limited, and several factors impede a classic multivariate analysis of epidemiologic data to resolve the issue. However, circumstantial evidence regarding postnatal exposure to the drug is abundant, and includes at least three otherwise unexplained temporal relationships, data from laboratory animal studies, several miscellaneous and otherwise unexplained correlations, and a lack of alternative suspects that fit the evidence-derived profile. Based on this evidence, it can be concluded without any reasonable doubt that oxidative stress puts some babies and children at risk of paracetamol-induced neurodevelopmental injury, and that postnatal exposure to paracetamol in those susceptible babies and children is responsible for many if not most cases of ASD.

Maternal use of acetaminophen during pregnancy and neurobehavioral problems in offspring at 3 years: A prospective cohort study

BACKGROUND

Acetaminophen is one of the most commonly used drugs during pregnancy globally. Recent studies have reported associations between prenatal exposure to acetaminophen and neurobehavioral problems in children, including attention-deficit hyperactivity disorders. Little research has investigated these associations in preschool-age children or the potential confounding effects of prenatal stress. The purpose of this study was to examine associations between prenatal acetaminophen exposure and offspring neurobehavioral problems at the age of 3 years, with a focus on the potentially confounding effects of prenatal stress.

METHODS

We used data from the First Baby Study, a prospective cohort study conducted in Pennsylvania, USA, with 2,423 mother-child pairs. Women reported medication use and completed a prenatal stress inventory during their third trimester. Child behavioral problems were measured at the age of 3 years, using the 7 syndrome scale scores from the Child Behavior Checklist (CBCL) for ages 1 ½ to 5.

RESULTS

There were 1,011 women (41.7%) who reported using acetaminophen during pregnancy. Children who were exposed to acetaminophen during pregnancy scored significantly higher on 3 of the 7 CBCL syndrome scales: withdrawn, sleep problems and attention problems. Scores on all 7 of the CBCL syndrome scales were significantly associated with prenatal stress. After adjustment for prenatal stress and other confounders, 2 syndrome scales remained significantly higher in children exposed to acetaminophen: sleep problems (aOR = 1.23, 95% CI = 1.01-1.51) and attention problems (aOR = 1.21, 95% CI = 1.01-1.45).

CONCLUSIONS

These findings corroborate previous studies reporting associations between prenatal exposure to acetaminophen and attention problems in offspring and also show an association with sleep problems at age 3 years. Because use of acetaminophen during pregnancy is common, these results are of public health concern and suggest caution in the use of medications containing acetaminophen during pregnancy.

Associations Between Pregnancy-Related Predisposing Factors for Offspring Neurodevelopmental Conditions and Parental Genetic Liability to Attention-Deficit/Hyperactivity Disorder, Autism, and Schizophrenia: The Norwegian Mother, Father and Child Cohort Study (MoBa)

Importance

Several maternal exposures during pregnancy are considered predisposing factors for offspring neurodevelopmental conditions. However, many of these exposures may be noncausal and biased by maternal genetic liability.

Objective

To assess whether pregnancy-related predisposing factors for offspring neurodevelopmental conditions are associated with maternal genetic liability for attention-deficit/hyperactivity disorder (ADHD), autism, and schizophrenia and to compare associations for maternal genetic liability with those for paternal genetic liability, which could indicate that paternal exposures are not suitable negative controls for maternal exposures.

Design, Setting, and Participants

The Norwegian Mother, Father and Child Cohort Study (MoBa) is a population-based pregnancy cohort that recruited parents from June 1999 to December 2008. Polygenic scores (PGS) for ADHD, autism, and schizophrenia were derived in mothers and fathers. The associations between maternal PGS and 37 pregnancy-related measures were estimated, and these results were compared with those from paternal PGS predicting paternal measures during the mother's pregnancy. Analysis took place between March 2021 and March 2022.

Exposures

PGS for ADHD, autism, and schizophrenia, calculated (using discovery effect size estimates and threshold of P < .05) from the largest available genome-wide association studies.

Main Outcomes and Measures

Self-reported pregnancy-related measures capturing lifestyle behaviors, metabolism, infectious and autoimmune diseases, other physical health conditions, and medication use.

Results

Data were available for up to 14 539 mothers (mean [SD] age, 30.00 [4.45] years) and 14 897 fathers (mean [SD] age, 32.46 [5.13] years) of European ancestry. Modest but robust associations were observed between specific pregnancy-related measures and maternal PGS, including ADHD PGS with asthma (odds ratio [OR], 1.15 [95% CI, 1.06-1.25]), smoking (OR, 1.26 [95% CI, 1.19-1.33]), prepregnancy body mass index (β, 0.25 [95% CI, 0.18-0.31]), pregnancy weight gain (β, 0.20 [95% CI, 0.10-0.30]), taking folate (OR, 0.92 [95% CI, 0.88-0.96]), and not taking supplements (OR, 1.09 [95% CI, 1.04-1.14]). Schizophrenia PGS was associated with coffee consumption (OR, 1.09 [95% CI, 1.05-1.12]), smoking (OR, 1.12 [95% CI, 1.06-1.19]), prepregnancy body mass index (β, -0.18 [95% CI, -0.25 to -0.11]), and pregnancy weight gain (β, 0.17 [95% CI, 0.07-0.27]). All 3 PGSs associated with symptoms of depression/anxiety (ADHD: OR, 1.15 [95% CI, 1.09-1.22]; autism: OR, 1.13 [95% CI, 1.06-1.19]; schizophrenia: OR, 1.13 [95% CI, 1.07-1.20]). Associations were largely consistent for maternal and paternal PGS, except ADHD PGS and smoking (fathers: OR, 1.13 [95% CI, 1.09-1.17]).

Conclusions and Relevance

In this study, genetic liability to neurodevelopmental conditions that is passed from mothers to children was associated with several pregnancy-related factors and may therefore confound associations between these pregnancy-related factors and offspring neurodevelopment that have previously been thought to be causal. It is crucial that future study designs account for genetic confounding to obtain valid causal inferences so that accurate advice can be given to pregnant individuals.

Low reliability of DNA methylation across Illumina Infinium platforms in cord blood: implications for replication studies and meta-analyses of prenatal exposures

Background

There is an increasing interest in the role of epigenetics in epidemiology, but the emerging research field faces several critical biological and technical challenges. In particular, recent studies have shown poor correlation of measured DNA methylation (DNAm) levels within and across Illumina Infinium platforms in various tissues. In this study, we have investigated concordance between 450 k and EPIC Infinium platforms in cord blood. We could not replicate our previous findings on the association of prenatal paracetamol exposure with cord blood DNAm, which prompted an investigation of cross-platform DNAm differences.

Results

This study is based on two DNAm data sets from cord blood samples selected from the Norwegian Mother, Father and Child Cohort Study (MoBa). DNAm of one data set was measured using the 450 k platform and the other data set was measured using the EPIC platform. Initial analyses of the EPIC data could not replicate any of our previous significant findings in the 450 k data on associations between prenatal paracetamol exposure and cord blood DNAm. A subset of the samples (n = 17) was included in both data sets, which enabled analyses of technical sources potentially contributing to the negative replication. Analyses of these 17 samples with repeated measurements revealed high per-sample correlations (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\stackrel{\mathrm{-}}{\text{R}}\hspace{0.17em}\approx$$\end{document}R-≈ 0.99), but low per-CpG correlations (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\stackrel{\mathrm{-}}{\text{R}}$$\end{document}R- ≈ 0.24) between the platforms. 1.7% of the CpGs exhibited a mean DNAm difference across platforms > 0.1. Furthermore, only 26.7% of the CpGs exhibited a moderate or better cross-platform reliability (intra-class correlation coefficient ≥ 0.5).

Conclusion

The observations of low cross-platform probe correlation and reliability corroborate previous reports in other tissues. Our study cannot determine the origin of the differences between platforms. Nevertheless, it emulates the setting in studies using data from multiple Infinium platforms, often analysed several years apart. Therefore, the findings may have important implications for future epigenome-wide association studies (EWASs), in replication, meta-analyses and longitudinal studies. Cognisance and transparency of the challenges related to cross-platform studies may enhance the interpretation, replicability and validity of EWAS results both in cord blood and other tissues, ultimately improving the clinical relevance of epigenetic epidemiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-022-01299-3.

Paracetamol perturbs neuronal arborization and disrupts the cytoskeletal proteins SPTBN1 and TUBB3 in both human and chicken in vitro models

Epidemiological studies have linked long-term/high-dose usage of paracetamol (N-acetyl-para-aminophenol, APAP) during pregnancy to adverse neuropsychiatric outcomes, primarily attention-deficit hyperactive disorder (ADHD), in the offspring. Though variable, ADHD has been associated with phenotypic alterations characterized by reductions in grey matter densities and aberrations in structural connectivity, effects which are thought to originate in neurodevelopment. We used embryonic chicken cerebellar granule neurons (CGNs) and neuronally differentiating human NTERA2 cells (NT2Ns) to investigate the in vitro effects of APAP on cell viability, migration, neuritogenesis, and the intracellular levels of various proteins involved in neurodevelopment as well as in the maintenance of the structure and function of neurites. Exposure to APAP ranging from 100 to 1600 μM yielded concentration- and time-dependent reductions in cell viability and levels of neurite arborization, as well as reductions in the levels of the cytoskeletal protein β2-spectrin, with the highest APAP concentration resulting in between 50 and 75% reductions in the aforementioned metrics over the course of 72 h. Exposure to APAP also reduced migration in the NT2Ns but not CGNs. Moreover, we found concentration- and time-dependent increases in punctate aggregation of the cytoskeletal protein β3-tubulin following exposure to APAP in both cell model systems, with the highest APAP concentration approximately doubling the number of aggregates over 72-120 h. Our findings demonstrate that APAP negatively perturbs neurite arborization degree, with concurrent reductions in the protein levels of β2-spectrin and disruption of the integrity of β3-tubulin, both proteins of which play important roles in neuronal structure and function.

Paracetamol (acetaminophen) use in infants and children was never shown to be safe for neurodevelopment: a systematic review with citation tracking

Although widely believed by pediatricians and parents to be safe for use in infants and children when used as directed, increasing evidence indicates that early life exposure to paracetamol (acetaminophen) may cause long-term neurodevelopmental problems. Furthermore, recent studies in animal models demonstrate that cognitive development is exquisitely sensitive to paracetamol exposure during early development. In this study, evidence for the claim that paracetamol is safe was evaluated using a systematic literature search. Publications on PubMed between 1974 and 2017 that contained the keywords "infant" and either "paracetamol" or "acetaminophen" were considered. Of those initial 3096 papers, 218 were identified that made claims that paracetamol was safe for use with infants or children. From these 218, a total of 103 papers were identified as sources of authority for the safety claim.   Conclusion: A total of 52 papers contained actual experiments designed to test safety, and had a median follow-up time of 48 h. None monitored neurodevelopment. Furthermore, no trial considered total exposure to drug since birth, eliminating the possibility that the effects of drug exposure on long-term neurodevelopment could be accurately assessed. On the other hand, abundant and sufficient evidence was found to conclude that paracetamol does not induce acute liver damage in babies or children when used as directed. What is Known: • Paracetamol (acetaminophen) is widely thought by pediatricians and parents to be safe when used as directed in the pediatric population, and is the most widely used drug in that population, with more than 90% of children exposed to the drug in some reports. • Paracetamol is known to cause liver damage in adults under conditions of oxidative stress or when used in excess, but increasing evidence from studies in humans and in laboratory animals indicates that the target organ for paracetamol toxicity during early development is the brain, not the liver. What is New: • This study finds hundreds of published reports in the medical literature asserting that paracetamol is safe when used as directed, providing a foundation for the widespread belief that the drug is safe. • This study shows that paracetamol was proven to be safe by approximately 50 short-term studies demonstrating the drug's safety for the pediatric liver, but the drug was never shown to be safe for neurodevelopment. Paracetamol is widely believed to be safe for infants and children when used as directed, despite mounting evidence in humans and in laboratory animals indicating that the drug is not safe for neurodevelopment. An exhaustive search of published work cited for safe use of paracetamol in the pediatric population revealed 52 experimental studies pointing toward safety, but the median follow-up time was only 48 h, and neurodevelopment was never assessed.

Paracetamol (Acetaminophen) and its Effect on the Developing Mouse Brain

Paracetamol, or acetaminophen (AAP), is the most commonly used analgesic during pregnancy and early life. While therapeutic doses of AAP are considered harmless during these periods, recent findings in both humans and rodents suggest a link between developmental exposure to AAP and behavioral consequences later in life. The aim of this study is to evaluate the impact of neonatal exposure to clinically relevant doses of AAP on adult spontaneous behavior, habituation, memory, learning, and cognitive flexibility later in life using a mouse model. Markers of oxidative stress, axon outgrowth, and glutamatergic transmission were also investigated in the hippocampus during the first 24 h after exposure. In addition, potential long-term effects on synaptic density in the hippocampus have been investigated. In a home cage setting, mice neonatally exposed to AAP (30 + 30 mg/kg, 4 h apart) on postnatal day 10 displayed altered spontaneous behavior and changed habituation patterns later in life compared to controls. These mice also displayed reduced memory, learning and cognitive flexibility compared to control animals in the Morris water maze. An increase of markers for oxidative stress was observed in the hippocampus 6 h after AAP exposure. As AAP is the first choice treatment for pain and/or fever during pregnancy and early life, these results may be of great importance for risk assessment. Here we show that AAP can have persistent negative effects on brain development and suggest that AAP, despite the relatively low doses, is capable to induce acute oxidative stress in the hippocampus.

Long-Term Safety of Prenatal and Neonatal Exposure to Paracetamol: A Systematic Review

Introduction: Paracetamol is the most commonly used antipyretic and analgesic in pregnancy. It is also increasingly used off-label in the neonatal intensive care unit. Despite the frequent use of paracetamol, concerns have been raised regarding the high variability in neonatal dosing regimens and the long-term safety of early life exposure. Objective: To investigate the available evidence on the long-term safety of prenatal and neonatal paracetamol exposure. Methods: We conducted a systematic search of the electronic databases Ovid Medline, Ovid Embase and Web of Science from inception to August 2021 for original research studies of any design that described the use of paracetamol in the prenatal or neonatal (within the first four weeks of life) periods and examined the occurrence of neurodevelopmental, atopic or reproductive adverse outcomes at or beyond birth. Results: We identified 1313 unique articles and included 30 studies in the final review. Of all studies, 27 (90%), two (7%) and one (3%) were on the long-term safety of prenatal, neonatal and both prenatal and neonatal exposure, respectively. Thirteen (46%), 11 (39%) and four (15%) studies examined neurodevelopmental, atopic and reproductive outcomes. Eleven (100%), 11 (100%), and three (27%) studies on prenatal exposure reported adverse neurodevelopmental, atopic and reproductive outcomes. Only one study found a possible correlation between neonatal paracetamol exposure and long-term adverse outcomes. Conclusions: The available evidence, although limited, suggests a possible association between prenatal paracetamol exposure and an increased risk of neurodevelopmental, atopic and reproductive adverse outcomes. There is an immediate need for robust data on the long-term safety of paracetamol exposure in the prenatal and neonatal periods.

Drug-induced Neuropsychiatric Adverse Events Using Post-Marketing Surveillance

BACKGROUND

Several studies reported that abnormal behavior was noted in pediatric patients receiving several drugs, including neuraminidase inhibitors (NIs). However, the information on drugs associated with abnormal behavior in a real-world setting remains limited. The purpose of this study was to clarify the drugs associated with abnormal behavior using a spontaneous reporting system database.

METHODS

We performed a retrospective pharmacovigilance disproportionality analysis using the Japanese Adverse Drug Event Report database. Adverse event reports submitted to the Pharmaceuticals and Medical Devices Agency were analyzed, and the reporting odds ratio at 95% confidence interval were calculated.

RESULTS

A total of 1,144 reports of abnormal behavior were identified. The signals were detected through the association of 4 neuraminidase inhibitors (oseltamivir, zanamivir, laninamivir, and peramivir) with the abnormal behaviour. These signals were stronger for oseltamivir than other neuraminidase inhibitors. The signals were also detected for acetaminophen and montelukast.

CONCLUSION

Our results should be able to raise physicians' awareness of drugs associated with abnormal behavior, but further investigation of these medications is warranted.

Paracetamol use during pregnancy - a call for precautionary action

Paracetamol (N-acetyl-p-aminophenol (APAP), otherwise known as acetaminophen) is the active ingredient in more than 600 medications used to relieve mild to moderate pain and reduce fever. APAP is widely used by pregnant women as governmental agencies, including the FDA and EMA, have long considered APAP appropriate for use during pregnancy when used as directed. However, increasing experimental and epidemiological research suggests that prenatal exposure to APAP might alter fetal development, which could increase the risks of some neurodevelopmental, reproductive and urogenital disorders. Here we summarize this evidence and call for precautionary action through a focused research effort and by increasing awareness among health professionals and pregnant women. APAP is an important medication and alternatives for treatment of high fever and severe pain are limited. We recommend that pregnant women should be cautioned at the beginning of pregnancy to: forego APAP unless its use is medically indicated; consult with a physician or pharmacist if they are uncertain whether use is indicated and before using on a long-term basis; and minimize exposure by using the lowest effective dose for the shortest possible time. We suggest specific actions to implement these recommendations. This Consensus Statement reflects our concerns and is currently supported by 91 scientists, clinicians and public health professionals from across the globe.

Paracetamol (Acetaminophen) and the Developing Brain

Paracetamol is commonly used to treat fever and pain in pregnant women, but there are growing concerns that this may cause attention deficit hyperactivity disorder and autism spectrum disorder in the offspring. A growing number of epidemiological studies suggests that relative risks for these disorders increase by an average of about 25% following intrauterine paracetamol exposure. The data analyzed point to a dose-effect relationship but cannot fully account for unmeasured confounders, notably indication and genetic transmission. Only few experimental investigations have addressed this issue. Altered behavior has been demonstrated in offspring of paracetamol-gavaged pregnant rats, and paracetamol given at or prior to day 10 of life to newborn mice resulted in altered locomotor activity in response to a novel home environment in adulthood and blunted the analgesic effect of paracetamol given to adult animals. The molecular mechanisms that might mediate these effects are unknown. Paracetamol has diverse pharmacologic actions. It reduces prostaglandin formation via competitive inhibition of the peroxidase moiety of prostaglandin H2 synthase, while its metabolite N-arachidonoyl-phenolamine activates transient vanilloid-subtype 1 receptors and interferes with cannabinoid receptor signaling. The metabolite N-acetyl-p-benzo-quinone-imine, which is pivotal for liver damage after overdosing, exerts oxidative stress and depletes glutathione in the brain already at dosages below the hepatic toxicity threshold. Given the widespread use of paracetamol during pregnancy and the lack of safe alternatives, its impact on the developing brain deserves further investigation.

Prenatal and postnatal exposure to acetaminophen in relation to autism spectrum and attention-deficit and hyperactivity symptoms in childhood: Meta-analysis in six European population-based cohorts

The potential etiological role of early acetaminophen exposure on Autism Spectrum Conditions (ASC) and Attention-Deficit/Hyperactivity Disorder (ADHD) is inconclusive. We aimed to study this association in a collaborative study of six European population-based birth/child cohorts. A total of 73,881 mother-child pairs were included in the study. Prenatal and postnatal (up to 18 months) acetaminophen exposure was assessed through maternal questionnaires or interviews. ASC and ADHD symptoms were assessed at 4-12 years of age using validated instruments. Children were classified as having borderline/clinical symptoms using recommended cutoffs for each instrument. Hospital diagnoses were also available in one cohort. Analyses were adjusted for child and maternal characteristics along with indications for acetaminophen use. Adjusted cohort-specific effect estimates were combined using random-effects meta-analysis. The proportion of children having borderline/clinical symptoms ranged between 0.9 and 12.9% for ASC and between 1.2 and 12.2% for ADHD. Results indicated that children prenatally exposed to acetaminophen were 19% and 21% more likely to subsequently have borderline or clinical ASC (OR = 1.19, 95% CI 1.07-1.33) and ADHD symptoms (OR = 1.21, 95% CI 1.07-1.36) compared to non-exposed children. Boys and girls showed higher odds for ASC and ADHD symptoms after prenatal exposure, though these associations were slightly stronger among boys. Postnatal exposure to acetaminophen was not associated with ASC or ADHD symptoms. These results replicate previous work and support providing clear information to pregnant women and their partners about potential long-term risks of acetaminophen use.

Perinatal Acetaminophen Exposure and Childhood Attention-Deficit/Hyperactivity Disorder (ADHD): Exploring the Role of Umbilical Cord Plasma Metabolites in Oxidative Stress Pathways

Oxidative stress mechanisms may explain associations between perinatal acetaminophen exposure and childhood attention-deficit hyperactivity disorder (ADHD). We investigated whether the changes in umbilical cord plasma amino acids needed to synthesize the antioxidant glutathione and in the oxidative stress biomarker 8-hydroxy-deoxyguanosine may explain the association between cord plasma acetaminophen and ADHD in the Boston Birth Cohort (BBC). Mother–child dyads were followed at the Boston Medical Center between 1998 and 2018. Cord plasma analytes were measured from archived samples collected at birth. Physician diagnoses of childhood ADHD were obtained from medical records. The final sample consisted of 568 participants (child mean age [SD]: 9.3 [3.5] years, 315 (52.8%) male, 248 (43.7%) ADHD, 320 (56.3%) neurotypical development). Cord unmetabolized acetaminophen was positively correlated with methionine (R = 0.33, p < 0.001), serine (R = 0.30, p < 0.001), glycine (R = 0.34, p < 0.001), and glutamate (R = 0.16, p < 0.001). Children with cord acetaminophen levels >50th percentile appeared to have higher risk of ADHD for each increase in cord 8-hydroxy-deoxyguanosine level. Adjusting for covariates, increasing cord methionine, glycine, serine, and 8-hydroxy-deoxyguanosine were associated with significantly higher odds for childhood ADHD. Cord methionine statistically mediated 22.1% (natural indirect effect logOR = 0.167, SE = 0.071, p = 0.019) and glycine mediated 22.0% (natural indirect effect logOR = 0.166, SE = 0.078, p = 0.032) of the association between cord acetaminophen >50th percentile with ADHD. Our findings provide some clues, but additional investigation into oxidative stress pathways and the association of acetaminophen exposure and childhood ADHD is warranted.

Self-Medication Among Pregnant Women: Prevalence and Associated Factors

Objectives: The pregnancy period, with its peculiarities and specific symptoms that may or may not be physiological, can lead to medication use through prescription or even self-medication. This study aimed to assess self-medication practices among pregnant women, the most used medications, symptoms reported, and factors associated with this practice. Methods: This was a cross-sectional study conducted with pregnant women with an antenatal care (ANC) appointment in a tertiary teaching hospital referral in women's health. From April 2019 to February 2020, 297 pregnant women were interviewed. Self-medication was considered as the use of any medicine (including medicinal plants (MPs), herbal products, and vitamins) without a medical or dental prescription. The period considered to assess self-medication practice was the last 60 days prior to the study interview. Results: Among the 297 women interviewed, 107 (36.0%) had practiced self-medication in the previous 60 days. Acetaminophen was the most used medication, and headache was the most frequent symptom reported by self-medicated pregnant women. Pregnant women with high-school (73 (68.2%) (OR = 2.52; 95% CI 1.17-5.43; p = 0.018)) or university-level (23 (21.5%) (OR = 2.82; 95% CI 1.15-6.94; p = 0.024)) education had a higher risk of practicing self-medication when compared to women with lower education. Women in the first gestational trimester (35 (32.7%) (OR = 3.61; 95% CI 1.64-7.96; p = 0.002)) and with two or more pregnancies (87 (81.2%) (OR = 1.96; 95% CI 1.07-3.60; p = 0.029)) were more likely to practice self-medication than pregnant women in the second or third gestational trimester and in the first pregnancy, respectively. Conclusion: Self-medication was practiced by a considerable proportion of our sample, with the majority being OTC drugs. The factors associated with self-medication can help to improve prevention strategies regarding self-medication during pregnancy.

Prenatal acetaminophen use in women with autoimmune disorders and adverse pregnancy and birth outcomes

OBJECTIVES

Most women may have temporary pain for which they use analgesics, but those with autoimmune disorders have chronic pain that may be exacerbated for some during pregnancy. This study aimed to determine whether prenatal acetaminophen use was associated with an increased risk of adverse pregnancy and birth outcomes in women with autoimmune disorders.

METHODS

Participants were enrolled between 2004 and 2018 in the MotherToBaby cohort study and limited to women with an autoimmune disorder (n = 1,821). Self-reported acetaminophen use was characterized over gestation for indication, timing of use and duration. Cumulative acetaminophen use through 20 and 32 weeks was categorized into quintiles, with no acetaminophen use as the reference category. The association between acetaminophen quintile and preeclampsia or pregnancy induced hypertension, small for gestational age (SGA), and preterm birth was examined using adjusted multiple log-linear regression.

RESULTS

Overall, 74% of women reported acetaminophen use during pregnancy. The most often reported indication for using acetaminophen was headache/migraines, followed by pain and injury. Risk of preeclampsia was 1.62 times greater for those in the fifth quintile of cumulative acetaminophen use through 20 weeks compared with those with no acetaminophen use (95% CI: 1.10, 2.40). There were no associations with lower use quintiles, nor for the other outcomes.

CONCLUSION

The highest quintile of cumulative acetaminophen was associated with a modestly increased risk for preeclampsia. Some women with autoimmune conditions have pain throughout pregnancy; clinicians and patients should discuss approaches to best avoid high levels of acetaminophen in their pain management strategies.

Therapeutic doses of acetaminophen with co-administration of cysteine and mannitol during early development result in long term behavioral changes in laboratory rats

Based on several lines of evidence, numerous investigators have suggested that acetaminophen exposure during early development can induce neurological disorders. We had previously postulated that acetaminophen exposure early in life, if combined with antioxidants that prevent accumulation of NAPQI, the toxic metabolite of acetaminophen, might be innocuous. In this study, we administered acetaminophen at or below the currently recommended therapeutic dose to male laboratory rat pups aged 4-10 days. The antioxidants cysteine and mannitol were included to prevent accumulation of NAPQI. In addition, animals were exposed to a cassette of common stress factors: an inflammatory diet, psychological stress, antibiotics, and mock infections using killed bacteria. At age 37-49 days, observation during introduction to a novel conspecific revealed increased rearing behavior, an asocial activity, in animals treated with acetaminophen plus antioxidants, regardless of their exposure to oxidative stress factors (2-way ANOVA; P < 0.0001). This observation would suggest that the initial hypothesis is incorrect, and that oxidative stress mediators do not entirely eliminate the effects of acetaminophen on neurodevelopment. This study provides additional cause for caution when considering the use of acetaminophen in the pediatric population, and provides evidence that the effects of acetaminophen on neurodevelopment need to be considered both in the presence and in the absence of oxidative stress.

Behavioral Problems at Age 11 Years After Prenatal and Postnatal Exposure to Acetaminophen: Parent-Reported and Self-Reported Outcomes

Several studies have reported associations between prenatal acetaminophen exposure and behavioral outcomes in young children. We aimed to evaluate the associations of prenatal and postnatal exposures to acetaminophen with behavioral problems in children at age 11 years, using behavioral measures reported by parents and children. We studied 40,934 mother-child pairs from the Danish National Birth Cohort enrolled during 1996-2002. Parent-reported and child-reported Strengths and Difficulties Questionnaire (SDQ) responses were collected during the 11-year follow-up. We estimated risk ratios for behavioral problems including total difficulties as well as internalizing or externalizing behaviors following prenatal (during pregnancy) or postnatal (within the first 18 months after birth) acetaminophen exposure. Parent-reported and child-reported SDQ scores were moderately correlated; higher for externalizing (r = 0.59) than internalizing (r = 0.49) behaviors. Prenatal acetaminophen exposure was associated with 10%-40% higher risks for total difficulties and internalizing and externalizing problems based on parent- or child-reported SDQ, with the association being stronger for greater cumulative weeks of acetaminophen use. Postnatal exposure was associated with 16%-19% higher risks for parent-reported internalizing behaviors, but the associations were weak or null for child-reported scores except for prosocial behavior. Our study corroborates published associations between prenatal exposures to acetaminophen and behavioral problems and extends the literature to early adolescence.

Intravenous paracetamol for neonates: long-term diseases not escalated during 5 years of follow-up

OBJECTIVE

To evaluate the long-term adverse reactions of paracetamol in children who required intensive care shortly after birth. Paracetamol is a widely used analgesic in neonates, but the long-term studies are lacking. Previous epidemiological studies have reported associations between early paracetamol intake and diseases in childhood.

DESIGN

Five-year follow-up cohort of children who required intensive care shortly after birth.

SETTING

Single tertiary care hospital; neonatal and paediatric intensive care units.

INTERVENTIONS

Intravenous paracetamol was administered for pain and discomfort to the neonates during their intensive care, while for the control infants, it was not available.

MAIN OUTCOME MEASURES

The primary outcome was the incidence of asthma; secondary outcomes were neonatal diseases and long-term morbidities (atopic dermatitis, inflammatory bowel disease, autism, speech disorders, cerebral palsy). Long-term morbidities were adjusted based on antenatal and neonatal risk factors.

RESULTS

We screened all neonates admitted to the intensive care units soon after birth in Oulu University Hospital, Oulu, Finland, during 1 October 2007 to 31 December 2013. Altogether, 1552 infants needed intensive care. Of them, 735 (47%) were treated with intravenous paracetamol. We obtained their long-term data from the Finnish National Institute for Health and Welfare, including all physician-made diagnoses from all primary healthcare units and hospitals in Finland. We found no difference in the asthma incidence or in other long-term morbidities between paracetamol-treated and non-exposed infants.

CONCLUSIONS

Intravenous paracetamol given to neonates did not associate with childhood disorders compared with the non-exposed infants during the 5-year follow-up. The previous hypothesis that early paracetamol use causes childhood morbidities was not confirmed.

Acetaminophen Attenuates invasion and alters the expression of extracellular matrix enzymes and vascular factors in human first trimester trophoblast cells

Acetaminophen is one of the most common medications taken during pregnancy, considered safe for maternal health and fetal development. However, recent epidemiological studies have associated prenatal acetaminophen use with several developmental disorders in offspring. As acetaminophen can freely cross into and through the placenta, epidemiological associations with prenatal acetaminophen use may reflect direct actions on the fetus and/or the impact of altered placental functions. In the absence of rigorous mechanistic studies, our understanding of how prenatal acetaminophen exposure can cause long-term effects in offspring is limited. The objective of this study was to determine whether acetaminophen can alter key functions of a major placental cell type by utilizing immortalized human first trimester trophoblast cells. This study employed a comparative analysis with the nonsteroidal, anti-inflammatory drug aspirin, which has established effects in first trimester trophoblast cells. We report that immortalized trophoblast cells express the target proteins of acetaminophen and aspirin: cyclooxygenase (COX) -1 and -2. Unlike aspirin, acetaminophen significantly repressed the expression of angiogenesis and vascular remodeling genes in HTR-8/SVneo cells. Moreover, acetaminophen impaired trophoblast invasion by over 80%, while aspirin had no effect on invasion. Acetaminophen exposure reduced the expression of matrix metalloproteinase (MMP)-2 and -9 and increased the expression of tissue inhibitors of matrix metalloproteinases 2, leading to an imbalance in the ratio of proteolytic enzymes. Finally, a bioinformatic approach identified novel acetaminophen-responsive gene networks associated with key trophoblast functions and disease. Together these results suggest that prenatal acetaminophen use may interfere with critical trophoblast functions early in gestation, which may subsequently impact fetal development.

Intrauterine Exposure to Acetaminophen and Adverse Developmental Outcomes: Epidemiological Findings and Methodological Issues

PURPOSE OF REVIEW

Acetaminophen (or paracetamol) is one of the most commonly used medications during pregnancy. We reviewed recent epidemiological evidence regarding intrauterine exposure to acetaminophen and risk for asthma, neurodevelopment disorders, and reproductive health in childhood.

RECENT FINDINGS

An increasing number of cohort studies have suggested that maternal use of acetaminophen during pregnancy was associated with increased risk for asthma; neurodevelopmental disorders, especially ADHD and behavioral problems; and genital malformations in the offspring. Oxidative stress and inflammation or endocrine effects are plausible shared biological mechanisms for the exposure to influence multiple developmental outcomes. We discussed methodological challenges that can threaten the validity of these observational data, including confounding and measurement errors. Novel statistical methods and research designs that can be used to mitigate these issues were introduced. Given the high prevalence of use, findings regarding intrauterine exposure to acetaminophen on multiple child health outcomes raise concerns. Research on causal and non-causal mechanisms that might explain these associations should be a priority.

Paracetamol - An old drug with new mechanisms of action

Paracetamol (acetaminophen) is the most commonly used over-the-counter (OTC) drug in the world. Despite its popularity and use for many years, the safety of its application and its mechanism of action are still unclear. Currently, it is believed that paracetamol is a multidirectional drug and at least several metabolic pathways are involved in its analgesic and antipyretic action. The mechanism of paracetamol action consists in inhibition of cyclooxygenases (COX-1, COX-2, and COX-3) and involvement in the endocannabinoid system and serotonergic pathways. Additionally, paracetamol influences transient receptor potential (TRP) channels and voltage-gated Kv7 potassium channels and inhibits T-type Cav3.2 calcium channels. It also exerts an impact on L-arginine in the nitric oxide (NO) synthesis pathway. However, not all of these effects have been clearly confirmed. Therefore, the aim of our paper was to summarize the current state of knowledge of the mechanism of paracetamol action with special attention to its safety concerns.

Neuropsychiatric Outcome of Children Born to Women With Systemic Lupus Erythematosus and Exposed in Utero to Azathioprine: A Case-Control Study

Objective: The long-term outcome of children born to SLE mothers still represents a controversial topic in literature, with some studies reporting a possible increased prevalence of different neurologic and psychiatric diseases (NPD), including neurodevelopmental disorders (ND), and in particular learning disorders (LD). Different risk factors have been advocated, such as the in utero exposure to auto-antibodies and drugs, particularly Azathioprine (AZA). Methods: A case-control study was designed to compare pregnancies treated with AZA (cases) with those not treated with AZA (controls). All the pregnancies had been prospectively followed in two Italian centers. The match was based upon renal involvement, antiphospholipid (aPL) status, maternal age at pregnancy (±5 years) and child's age at the time of the study (±2 years). SLE mothers were interviewed by a telephone survey, particularly focused on the presence of a certified NPD in their children ≥6 years of age. Results: Twenty-seven cases and 65 controls were similar in terms of demographic, immunological and clinical features, except for a higher rate of SLE flares during pregnancy in cases (22.2% vs. 10.8%, p:0.191). The 92 children had a mean age of 14.0 years at the time of the survey; 11 had at least one NPD (12.0%). The frequency of each single NPD was similar to that of the general pediatric population and no association was found with either the in utero exposure to AZA, or other specific factors (auto-antibodies, disease activity, obstetric complications, prematurity). Conclusion: The long-term neuropsychiatric outcome of the children born to SLE mothers did not show neither an increased frequency of NPD as compared to the general pediatric population nor a specific pattern of NPD. The in utero exposure to AZA was not associated with the development of NPD in this case-control study of prospectively-followed pregnancies. NPD are complex conditions and large prospective studies are needed to capture the wide range of variables that may contribute to their development in the offspring of SLE women.

Association of Prenatal Acetaminophen Exposure Measured in Meconium With Risk of Attention-Deficit/Hyperactivity Disorder Mediated by Frontoparietal Network Brain Connectivity

Importance

Despite evidence of an association between prenatal acetaminophen exposure and attention-deficit/hyperactivity disorder (ADHD) in offspring, the drug is not contraindicated during pregnancy, possibly because prior studies have relied on maternal self-report, failed to quantify acetaminophen dose, and lacked mechanistic insight.

Objective

To examine the association between prenatal acetaminophen exposure measured in meconium (hereinafter referred to as meconium acetaminophen) and ADHD in children aged 6 to 7 years, along with the potential for mediation by functional brain connectivity.

Design, Setting, and Participants

This prospective birth cohort study from the Centre Hospitalier Université de Sherbrooke in Sherbrooke, Québec, Canada, included 394 eligible children, of whom 345 had meconium samples collected at delivery and information on ADHD diagnosis. Mothers were enrolled from September 25, 2007, to September 10, 2009, at their first prenatal care visit or delivery and were followed up when children were aged 6 to 7 years. When children were aged 9 to 11 years, resting-state brain connectivity was assessed with magnetic resonance imaging. Data for the present study were collected from September 25, 2007, to January 18, 2020, and analyzed from January 7, 2019, to January 22, 2020.

Exposures

Acetaminophen levels measured in meconium.

Main Outcomes and Measures

Physician diagnosis of ADHD was determined at follow-up when children were aged 6 to 7 years or from medical records. Resting-state brain connectivity was assessed with magnetic resonance imaging; attention problems and hyperactivity were assessed with the Behavioral Assessment System for Children Parent Report Scale. Associations between meconium acetaminophen levels and outcomes were estimated with linear and logistic regressions weighted on the inverse probability of treatment to account for potential confounders. Causal mediation analysis was used to test for mediation of the association between prenatal acetaminophen exposure and hyperactivity by resting-state brain connectivity.

Results

Among the 345 children included in the analysis (177 boys [51.3%]; mean [SD] age, 6.58 [0.54] years), acetaminophen was detected in 199 meconium samples (57.7%), and ADHD was diagnosed in 33 children (9.6%). Compared with no acetaminophen, detection of acetaminophen in meconium was associated with increased odds of ADHD (odds ratio [OR], 2.43; 95% CI, 1.41-4.21). A dose-response association was detected; each doubling of exposure increased the odds of ADHD by 10% (OR, 1.10; 95% CI, 1.02-1.19). Children with acetaminophen detected in meconium showed increased negative connectivity between frontoparietal and default mode network nodes to clusters in the sensorimotor cortices, which mediated an indirect effect on increased child hyperactivity (14%; 95% CI, 1%-26%).

Conclusions and Relevance

Together with the multitude of other cohort studies showing adverse neurodevelopment associated with prenatal acetaminophen exposure, this work suggests caution should be used in administering acetaminophen during pregnancy. Research into alternative pain management strategies for pregnant women could be beneficial.

Environmental risk factors, protective factors, and peripheral biomarkers for ADHD: an umbrella review

BACKGROUND

Many potential environmental risk factors, environmental protective factors, and peripheral biomarkers for ADHD have been investigated, but the consistency and magnitude of their effects are unclear. We aimed to systematically appraise the published evidence of association between potential risk factors, protective factors, or peripheral biomarkers, and ADHD.

METHODS

In this umbrella review of meta-analyses, we searched PubMed including MEDLINE, Embase, and the Cochrane Database of Systematic Reviews, from database inception to Oct 31, 2019, and screened the references of relevant articles. We included systematic reviews that provided meta-analyses of observational studies that examined associations of potential environmental risk factors, environmental protective factors, or peripheral biomarkers with diagnosis of ADHD. We included meta-analyses that used categorical ADHD diagnosis criteria according to DSM, hyperkinetic disorder according to ICD, or criteria that were less rigorous than DSM or ICD, such as self-report. We excluded articles that did not examine environmental risk factors, environmental protective factors, or peripheral biomarkers of ADHD; articles that did not include a meta-analysis; and articles that did not present enough data for re-analysis. We excluded non-human studies, primary studies, genetic studies, and conference abstracts. We calculated summary effect estimates (odds ratio [OR], relative risk [RR], weighted mean difference [WMD], Cohen's d, and Hedges' g), 95% CI, heterogeneity I² statistic, 95% prediction interval, small study effects, and excess significance biases. We did analyses under credibility ceilings, and assessed the quality of the meta-analyses with AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews 2). This study is registered with PROSPERO, number CRD42019145032.

FINDINGS

We identified 1839 articles, of which 35 were eligible for inclusion. These 35 articles yielded 63 meta-analyses encompassing 40 environmental risk factors and environmental protective factors (median cases 16 850, median population 91 954) and 23 peripheral biomarkers (median cases 175, median controls 187). Evidence of association was convincing (class I) for maternal pre-pregnancy obesity (OR 1·63, 95% CI 1·49 to 1·77), childhood eczema (1·31, 1·20 to 1·44), hypertensive disorders during pregnancy (1·29, 1·22 to 1·36), pre-eclampsia (1·28, 1·21 to 1·35), and maternal acetaminophen exposure during pregnancy (RR 1·25, 95% CI 1·17 to 1·34). Evidence of association was highly suggestive (class II) for maternal smoking during pregnancy (OR 1·6, 95% CI 1·45 to 1·76), childhood asthma (1·51, 1·4 to 1·63), maternal pre-pregnancy overweight (1·28, 1·21 to 1·35), and serum vitamin D (WMD -6·93, 95% CI -9·34 to -4·51).

INTERPRETATION

Maternal pre-pregnancy obesity and overweight; pre-eclampsia, hypertension, acetaminophen exposure, and smoking during pregnancy; and childhood atopic diseases were strongly associated with ADHD. Previous familial studies suggest that maternal pre-pregnancy obesity, overweight, and smoking during pregnancy are confounded by familial or genetic factors, and further high-quality studies are therefore required to establish causality.

FUNDING

None.

Over-the-counter analgesics during pregnancy: a comprehensive review of global prevalence and offspring safety

BACKGROUND

Analgesia during pregnancy is often necessary. Due to their widespread availability, many mothers opt to use over-the-counter (OTC) analgesics. Those analgesic compounds and their metabolites can readily cross the placenta and reach the developing foetus. Evidence for safety or associations with adverse health outcomes is conflicting, limiting definitive decision-making for healthcare professionals.

OBJECTIVE AND RATIONALE

This review provides a detailed and objective overview of research in this field. We consider the global prevalence of OTC analgesia during pregnancy, explain the current mechanistic understanding of how analgesic compounds cross the placenta and reach the foetus, and review current research on exposure associations with offspring health outcomes.

SEARCH METHODS

A comprehensive English language literature search was conducted using PubMed and Scopus databases. Different combinations of key search terms were used including 'over-the-counter/non-prescription analgesics', 'pregnancy', 'self-medication', 'paracetamol', 'acetaminophen', 'diclofenac', 'aspirin', 'ibuprofen', 'in utero exposure', 'placenta drug transport', 'placental transporters', 'placenta drug metabolism' and 'offspring outcomes'.

OUTCOMES

This article examines the evidence of foetal exposure to OTC analgesia, starting from different routes of exposure to evidence, or the lack thereof, linking maternal consumption to offspring ill health. There is a very high prevalence of maternal consumption of OTC analgesics globally, which is increasing sharply. The choice of analgesia selected by pregnant women differs across populations. Location was also observed to have an effect on prevalence of use, with more developed countries reporting the highest consumption rates. Some of the literature focuses on the association of in utero exposure at different pregnancy trimesters and the development of neurodevelopmental, cardiovascular, respiratory and reproductive defects. This is in contrast to other studies which report no associations.

WIDER IMPLICATIONS

The high prevalence and the challenges of reporting exact consumption rates make OTC analgesia during pregnancy a pressing reproductive health issue globally. Even though some healthcare policy-making authorities have declared the consumption of some OTC analgesics for most stages of pregnancy to be safe, such decisions are often based on partial review of literature. Our comprehensive review of current evidence highlights that important knowledge gaps still exist. Those areas require further research in order to provide pregnant mothers with clear guidance with regard to OTC analgesic use during pregnancy.

Association between maternal acetaminophen use and adverse birth outcomes in a pregnancy and birth cohort

INTRODUCTION

Acetaminophen is the only analgesic recommended for use during pregnancy. This use has recently been linked to childhood developmental disorders, a finding that requires further investigation. Adverse birth outcomes-preterm birth, low birthweight, and small for gestational age-are associated with increased risk of developmental disorders and can serve as intermediate outcomes when examining the impact of maternal acetaminophen use.

METHODS

Clinical and lifestyle-factor data were gathered from 1200 women within the Ontario Birth Study who delivered between January 2013 and June 2017. Poisson regression with robust error variance was used to estimate the relationship between acetaminophen use before and during pregnancy and low birthweight, preterm birth, and small for gestational age.

RESULTS

Offspring of mothers who used acetaminophen before pregnancy had a higher risk of low birthweight and small for gestational age. Acetaminophen use <once/week was associated with small for gestational age, adjusted relative risk (aRR) = 1.46 (95% CI 1.02, 2.11). Acetaminophen use ≥once/week was associated with both small for gestational age, RR = 1.82 (95% CI 1.12, 2.94), and low birthweight, aRR = 2.16 (95% CI 1.02, 4.54). Acetaminophen use during pregnancy was not associated with the examined outcomes.

CONCLUSIONS

Prepregnancy acetaminophen use may be associated with higher risk of adverse birth outcomes.

Medications for pregnant women: A balancing act between the interests of the mother and of the fetus

Drug entry into the adult brain is controlled by efflux mechanisms situated in various brain barrier interfaces. The effectiveness of these protective mechanisms in the embryo, fetus and newborn brain is less clear. The longstanding belief that "the" blood-brain barrier is absent or immature in the fetus and newborn has led to many misleading statements with potential clinical implications. Here we review the properties of brain barrier mechanisms in the context of drug entry into the developing brain and discuss the limited number of studies published on the subject. We noticed that most of available literature suffers from some experimental limitations, notably that drug levels in fetal blood and cerebrospinal fluid have not been measured. This means that the relative contribution to the overall brain protection provided by individual barriers such as the placenta (which contains similar efflux mechanisms) and the brain barriers cannot be separately ascertained. Finally, we propose that systematic studies in appropriate animal models of drug entry into the brain at different stages of development would provide a rational basis for use of medications in pregnancy and in newborns, especially prematurely born, where protection usually provided by the placenta is no longer present.

Paternal antidepressant use as a negative control for maternal use: assessing familial confounding on gestational length and anxiety traits in offspring

Background

Maternal antidepressant use in pregnancy has been associated with both shorter gestational length and child anxiety. We employed paternal antidepressant use as a negative-control exposure to indirectly assess whether confounding by genetic or shared familial environmental factors associated with depression may explain these associations.

Methods

The study sample came from the population-based Norwegian Mother and Child Cohort Study (MoBa) that recruited participants from 1999 to 2008. We included 70 959 families where the father completed a questionnaire about medication use in the 6 months prior to pregnancy. In 42 511 infants who completed the 3-year follow-up, we computed Z-scores for the anxiety domain of the Child Behavior Checklist. We used linear and logistic regression to assess the association between paternal antidepressant use, gestational age at birth and child anxiety.

Results

Antidepressants were used by 1.1% (n = 755) of fathers. Paternal antidepressant use was not associated with gestational age at birth [β = 0.63 days, 95% confidence interval (CI) –1.56, 0.31] whereas it was positively associated with a child anxiety symptom Z-score and high anxiety symptoms (odds ratio 1.33, 95% CI 0.90, 1.97) in unadjusted analyses. This association was attenuated when controlling for maternal and paternal history of depression and other measured factors (odds ratio 1.14, 95% CI 0.76, 1.69).

Conclusions

These results support the suggested effect of maternal use of antidepressants in pregnancy on shorter gestation; however, they suggest familial confounding could explain the association between maternal use of antidepressants and anxiety traits in the offspring.

Maternal acetaminophen use during pregnancy and childhood behavioural problems: Discrepancies between mother- and teacher-reported outcomes

BACKGROUND

Maternal acetaminophen use during pregnancy is common and has been associated with childhood behavioural problems among offspring, specifically hyperactivity and conduct problems.

OBJECTIVE

Assessments of child behaviour in many previous studies have relied on maternal or parent report. Acknowledging that results of behavioural assessments vary between informants, we examined the association between maternal acetaminophen use during pregnancy and behaviour problems in childhood based on mother- and teacher-report.

METHODS

A longitudinal study of 560 mother-child pairs with data on illnesses and medication use during pregnancy and neurodevelopmental assessments during childhood was conducted. Acetaminophen use during pregnancy was captured using a standardised maternal interview, completed 1 year after delivery on average. Measures of childhood (6-12 years of age) behaviour were obtained via mother- and teacher-report, using the Child Behaviour Checklist and Teacher Report Form. Linear and log-binomial models were used to calculate adjusted mean differences (MD) and risk ratios (RR), respectively and 95% confidence intervals (CI) for internalising, externalising, and total behaviour problems comparing acetaminophen users to non-users. Stabilized inverse probability weights were used to account for loss to follow-up, and adjustments for indication were made.

RESULTS

Approximately 60% (n = 354) of women reported use of acetaminophen during pregnancy. Acetaminophen use during pregnancy was associated with an increase in total behaviour problem score and risk of clinical behaviour problems according to mother report (MD 2.2, 95% CI 0.3, 4.1 and RR 1.93, 95% CI 0.99, 3.76) but not according to teacher report. Weighting to account for participation did not alter results, while adjustment for indications of acetaminophen use greatly attenuated the associations with mother-reported total behaviour problem score and risk of clinical behaviour problems (MD 0.1, 95% CI -2.1, 2.3 and RR 1.31, 95% CI 0.67, 2.58).

CONCLUSIONS

Acetaminophen use during pregnancy was weakly associated with mother-reported behaviour problems and not associated with teacher-reported problems.

Acetaminophen use during pregnancy and the risk of attention deficit hyperactivity disorder: A causal association or bias?

BACKGROUND

The association between acetaminophen use during pregnancy and the development of attention deficit hyperactivity disorder (ADHD) in the offspring may be due to bias.

OBJECTIVES

The primary objective was to assess the role of potential unmeasured confounding in the estimation of the association between acetaminophen use during pregnancy and the risk of ADHD, through bias analysis. The secondary objective was to assess the roles of selection bias and exposure misclassification.

DATA SOURCES

We searched MEDLINE, Embase, Scopus, and the Cochrane Library up to December 2018.

STUDY SELECTION AND DATA EXTRACTION

We included observational studies examining the association between acetaminophen use during pregnancy and the risk of ADHD.

SYNTHESIS

We meta-analysed data across studies, using random-effects model. We conducted a bias analysis to studies that did not adjust for important confounders, to explore systematic errors related to unmeasured confounding, selection bias, and exposure misclassification.

RESULTS

The search resulted in seven studies included in our meta-analysis. When adjusted estimates were pooled across all studies, the risk ratio (RR) for ADHD was 1.35 (95% confidence interval [CI] 1.25, 1.46; I²  = 48%). Sensitivity analysis for unmeasured confounding in this meta-analysis showed that a confounder of 1.69 on the RR scale would reduce to 10% the proportion of studies with a true effect size of RR >1.10. Unmeasured confounding bias analysis decreased the point estimate in five of the seven studies and increased in two studies, suggesting that the observed association could be confounded by parental ADHD. Unadjusted and bias-corrected risk ratios (bcRRs) were: RR = 1.34, bcRR = 1.13; RR = 1.51, bcRR = 1.17; RR = 1.63, bcRR = 1.38; RR = 1.44, bcRR = 1.17; RR = 1.16, bcRR = 1.18; RR = 1.25, bcRR = 1.05; and RR = 0.99, bcRR = 1.18.

CONCLUSIONS

Bias analysis suggests that the previously reported association between acetaminophen use during pregnancy and an increased risk of ADHD in the offspring may be due to unmeasured confounding. Our ability to conclude a causal association is limited.

Prenatal paracetamol exposure and neurodevelopmental outcomes in preschool-aged children

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.

Associations between paracetamol (acetaminophen) intake between 18 and 32 weeks gestation and neurocognitive outcomes in the child: A longitudinal cohort study

BACKGROUND

The majority of epidemiological studies concerning possible adverse effects of paracetamol (acetaminophen) in pregnancy have been focussed on childhood asthma. Initial results of a robust association have been confirmed in several studies. Recently, a few cohort studies have looked at particular neurocognitive outcomes, and several have implicated hyperactivity.

OBJECTIVES

In order to confirm these findings, further information and results are required. Here, we assess whether paracetamol intake between 18 and 32 weeks gestation is associated with childhood behavioural and cognitive outcomes using a large population.

METHODS

Data collected by the Avon Longitudinal Study of Parents and Children (ALSPAC) at 32 weeks gestation and referring to the period from 18 to 32 weeks, identified 43.9% of women having taken paracetamol. We used an exposome analysis first to determine the background factors associated with pregnant women taking the drug, and then allowed for those factors to assess associations with child outcomes (measured using regression analyses).

RESULTS

We identified 15 variables independently associated with taking paracetamol in this time period, which were used as potential confounders. Of the 135 neurocognitive variables considered, adjusting for the likelihood of false discovery, we identified 56 outcomes for adjusted analyses. Adjustment identified 12 showing independent associations with paracetamol use at P < .05, four of which were at P < .0001 (all related to child behaviours reported by the mother at 42 and 47 months; eg conduct problems: adjusted mean score + 0.22 (95% confidence interval 0.10, 0.33)). There were few associations with behavioural or neurocognitive outcomes after age 7-8 years, whether reported by the mother or the teacher.

CONCLUSIONS

If paracetamol use in mid-to-late pregnancy has an adverse effect on child neurocognitive outcome, it appears to mainly relate to the pre-school period. It is important that these results be tested using other datasets or methodologies before assuming that they are causal.

Associations of acetaminophen use during pregnancy and the first year of life with neurodevelopment in early childhood

BACKGROUND

Over-the-counter analgesic use during pregnancy, particularly acetaminophen, may be associated with negative developmental outcomes in children.

OBJECTIVE

Estimate associations of prenatal and early-life exposure to acetaminophen in early childhood with cognitive, motor, and language skills in two birth cohorts.

METHODS

The American Project Viva cohort (1217 mother-child pairs enrolled 1999-2002) assessed cognition at approximately 3 years using the Peabody Picture Vocabulary Test and the Wide Range Achievement of Visual Motor Abilities (WRAVMA). The Brazilian 2015 Pelotas Birth Cohort (3818 mother-child pairs) assessed cognition at 2 years using the INTERGROWTH-21st Neurodevelopment Assessment. We used linear regression to estimate associations of acetaminophen use during pregnancy (Project Viva and Pelotas) and infancy (Project Viva) with children's cognitive scores adjusted for maternal age, pre-pregnancy body mass index, education, parity, race/ethnicity, smoking and alcohol use during pregnancy, depression during pregnancy, antibiotic and ibuprofen use during pregnancy, household income, and child's sex.

RESULTS

In Project Viva, exposure to acetaminophen in both the 1st and 2nd trimester of pregnancy was associated with lower WRAVMA drawing scores (β -1.51, 95% CI -2.92, -0.10). However, in Pelotas, exposure to acetaminophen in both the 1st and 2nd trimester of pregnancy was not associated with INTER-NDA motor scores (β 0.02; 95% CI -0.05, 0.09) and was associated with higher INTER-NDA total scores (β 0.08, 95% CI 0.01, 0.16). Other comparisons did not show evidence for any associations.

CONCLUSIONS

Inconsistencies and lack of specificity of the findings did not clarify the research question considering that we still have a large variability and uncertainty to define the risk or safety in the use of acetaminophen related to cognition in early childhood. More studies using better exposure assessment and better confounding variables are needed to clarify these associations.

Acetaminophen use in pregnancy: Examining prevalence, timing, and indication of use in a prospective birth cohort

BACKGROUND

Previous studies of prenatal acetaminophen use have not addressed what indications and maternal co-factors describe acetaminophen use.

OBJECTIVE

The objective of this study was to describe these parameters in a well-characterised, prospective birth cohort.

METHODS

Data were drawn from the MotherToBaby study of pregnant women enrolled from 2004 to 2018. Daily acetaminophen diaries were calculated for all exposed women with complete dose and duration information. Descriptive statistics were used to assess maternal characteristics associated with acetaminophen use. Prevalence by 2-year interval was described, and linear regression was used to test for trend. Indication of use and dose per indication were summarised.

RESULTS

Of 2441 subjects, 1515 (62%) reported use of acetaminophen. Over the 15-year period, there was a decline in use of 2.5% for each 2-year period (test for trend = 0.001) with 58% reporting acetaminophen use in 2017-2018. Among women with acetaminophen use in pregnancy (n = 1515), 58% reported <10 days of use, 13% reported 10-19 days of use, 9% reported 20-44 days of use, and 9% reported 45 or more days of use. Twelve per cent had undefined duration of use. Increasing duration of exposure was associated with tobacco use, obesity, self-reported depression or anxiety, and antidepressant use. The most frequently reported indication was headache, however, indication varied by duration of use, with more women reporting use for sleep or pain/injury in the categories with the longest duration of use. Median dose per exposed day was highest among those reporting use for sleep, and higher doses were more frequently reported for arthritis, injury, and pain.

CONCLUSION

Acetaminophen is used by the majority of pregnant women, and some continue to use for many weeks in pregnancy. Given the heterogeneity in duration of use, indication, and dose, studies that estimate the risk of adverse outcomes associated with acetaminophen must carefully consider these factors.