Examining the association between maternal analgesic use during pregnancy and risk of psychotic symptoms during adolescence

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.

Markers of Psychosis Risk in the General Population

The categorical approach to defining schizophrenia spectrum disorders requires meeting established criteria. To advance early identification and intervention in young people, the field has progressed to studying help-seeking individuals who are at clinical high risk based on subthreshold psychosis spectrum symptoms, and criteria have been articulated for qualifying individuals as at risk. A broader dimensional examination of psychosis has been applied to population-based studies on non-help seekers. This review highlights the ascertainment and assessment approaches to such population-based studies. Most studies are cross-sectional and rely on questionnaires with limited overlap of tools. However, several consistent findings emerge on symptoms, neurocognitive deficits, and neuroimaging parameters and other biomarkers associated with emergence and persistence of psychotic features. The findings are consistent with the literature on abnormalities associated with schizophrenia, including the presence of neurocognitive deficits; abnormalities in brain structure, function, and connectivity that are related to distress; impairment; and functional outcome. These findings support the validity of studying psychosis experiences during development in a way that can chart the emergence of psychosis in the context of general psychopathology. Such studies are necessary for establishing developmental trajectories that characterize this emergence and for identifying risk and resilience biomarkers moderating or modulating the full range of schizophrenia-related manifestations. More community-based studies are needed, with better standardization and harmonization of measures and incorporating longitudinal follow-up, to establish mechanistic links between cellular-molecular aberrations and specific manifestations of psychosis as envisioned by the precision medicine agenda.

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.

The impact of peri-natal stress on psychosis risk: results from the Bo-FEP incidence study

Objective

According to the gene-environment interaction model the pathogenesis of psychosis relies on an adverse neuro-socio-developmental pathway. Perinatal stress represents an important risk factor for the development of psychosis because of the increasingly evident interference with socio-neuro-development in the earlier phases of life. We aim to investigate the correlation of perinatal risk factors with the onset of psychosis with a case–control–incidence study.

Results

Patients (and their mothers) were eligible if they presented with first-episode psychosis at the Bologna West Community Mental Health Centre (Bo-West CMHC) between 2002 and 2012. The Bo-West CMHC serves a catchment area of about 200,000 people. The controls were recruited in the same catchment area and study period. 42 patients, 26 controls and their mothers were included. We collected the history of peri-natal stress and calculated crude and adjusted Odds Ratios for onset of first-episode psychosis. Adjusted logistic regression showed that psychosis onset was significantly associated with stressful situations during pregnancy, lower level of maternal physical health before or during pregnancy, use of anti-inflammatory drugs during pregnancy, and low level of maternal education. The results of our study suggest that stress during perinatal period increases the risk of developing psychosis.

The Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort as a resource for studying psychopathology in childhood and adolescence: a summary of findings for depression and psychosis

PURPOSE

The purpose of this study is to highlight the Avon Longitudinal Study of Parents and Children (ALSPAC) as a resource to study psychopathology. To demonstrate this, we review the studies related to depression and psychosis in childhood and adolescence and discuss the results in relation to the aetiology of depression and psychotic experiences (PEs) and possible underlying mechanisms.

METHODS

We examined the list of publications from ALSPAC and then classified them as examining (a) the course and risk factors of maternal and paternal depression, (b) the effects of maternal and paternal depression on child development, (c) risk factors for depression in childhood and adolescence, (d) the frequency, clinical relevance and risk factors of PEs, and (e) shared risk factors for depression and PEs.

RESULTS

There was evidence that environmental stressors and the way these are interpreted contribute to risk of depression and evidence that biological factors related to puberty are also likely to play a role. With regards to PEs, the findings further support the existence of 'a continuum of psychosis' while they also suggest that PEs might be of limited clinical utility in predicting psychotic disorder during adolescence and early adulthood. Finally, most risk factors examined were found to be shared between depression and PEs.

CONCLUSIONS

The ALSPAC birth cohort has provided important insights for our understanding of the aetiological mechanisms underlying depression and PEs. Future research could aim to incorporate measures of automatic psychological mechanisms to provide insights into the brain mechanisms that underlie these clinical phenomena.

Fetal programming of schizophrenia: select mechanisms

Mounting evidence indicates that schizophrenia is associated with adverse intrauterine experiences. An adverse or suboptimal fetal environment can cause irreversible changes in brain that can subsequently exert long-lasting effects through resetting a diverse array of biological systems including endocrine, immune and nervous. It is evident from animal and imaging studies that subtle variations in the intrauterine environment can cause recognizable differences in brain structure and cognitive functions in the offspring. A wide variety of environmental factors may play a role in precipitating the emergent developmental dysregulation and the consequent evolution of psychiatric traits in early adulthood by inducing inflammatory, oxidative and nitrosative stress (IO&NS) pathways, mitochondrial dysfunction, apoptosis, and epigenetic dysregulation. However, the precise mechanisms behind such relationships and the specificity of the risk factors for schizophrenia remain exploratory. Considering the paucity of knowledge on fetal programming of schizophrenia, it is timely to consolidate the recent advances in the field and put forward an integrated overview of the mechanisms associated with fetal origin of schizophrenia.

Population impact of familial and environmental risk factors for schizophrenia: a nationwide study

Although several studies have examined the relative contributions of familial and environmental risk factors for schizophrenia, few have additionally examined the predictive power on the individual level and simultaneously examined the population impact associated with a wide range of familial and environmental risk factors. The authors present rate ratios (IRR), population-attributable risks (PAR) and sex-specific cumulative incidences of the following risk factors: parental history of mental illness, urban place of birth, advanced paternal age, parental loss and immigration status. We established a population-based cohort of 2,486,646million persons born in Denmark between 1 January 1955 and 31 December 1993 using Danish registers. We found that PAR associated with urban birth was 11.73%; PAR associated with one, respectively 2, parent(s) with schizophrenia was 2.67% and 0.12%. PAR associated with second-generation immigration was 0.70%. Highest cumulative incidence (CI=20.23%; 95% CI=18.10-22.62) was found in male offspring of 2 parents with schizophrenia. Cumulative incidences for male offspring or female offspring of a parent with schizophrenia were 9.53% (95% CI=7.71-11.79), and 4.89%, (95% CI 4.50-5.31). The study showed that risk factors with highest predictive power on the individual level have a relatively low population impact. The challenge in future studies with direct genetic data is to examine gene-environmental interactions that can move research beyond current approaches and seek to achieve higher predictive power on the individual level and higher population impact.

Prenatal and perinatal analgesic exposure and autism: an ecological link

BACKGROUND

Autism and Autism Spectrum Disorder (ASD) are complex neurodevelopmental disorders. Susceptibility is believed to be the interaction of genetic heritability and environmental factors. The synchronous rises in autism/ASD prevalence and paracetamol (acetaminophen) use, as well as biologic plausibility have led to the hypothesis that paracetamol exposure may increase autism/ASD risk.

METHODS

To explore the relationship of antenatal paracetamol exposure to ASD, population weighted average autism prevalence rates and paracetamol usage rates were compared. To explore the relationship of early neonatal paracetamol exposure to autism/ASD, population weighted average male autism prevalence rates for all available countries and U.S. states were compared to male circumcision rates - a procedure for which paracetamol has been widely prescribed since the mid-1990s. Prevalence studies were extracted from the U.S. Centers for Disease Control and Prevention Summary of Autism/ASD Prevalence Studies database. Maternal paracetamol usage and circumcision rates were identified by searches on Pub Med.

RESULTS

Using all available country-level data (n = 8) for the period 1984 to 2005, prenatal use of paracetamol was correlated with autism/ASD prevalence (r = 0.80). For studies including boys born after 1995, there was a strong correlation between country-level (n = 9) autism/ASD prevalence in males and a country's circumcision rate (r = 0.98). A very similar pattern was seen among U.S. states and when comparing the 3 main racial/ethnic groups in the U.S. The country-level correlation between autism/ASD prevalence in males and paracetamol was considerably weaker before 1995 when the drug became widely used during circumcision.

CONCLUSIONS

This ecological analysis identified country-level correlations between indicators of prenatal and perinatal paracetamol exposure and autism/ASD. State level correlation was also identified for the indicator of perinatal paracetamol exposure and autism/ASD. Like all ecological analyses, these data cannot provide strong evidence of causality. However, biologic plausibility is provided by a growing body of experimental and clinical evidence linking paracetamol metabolism to pathways shown to be important in autism and related developmental abnormalities. Taken together, these ecological findings and mechanistic evidence suggest the need for formal study of the role of paracetamol in autism.

Prenatal inflammation and neurodevelopment in schizophrenia: a review of human studies

A confluence of evidence supports an association between prenatal inflammation and risk of schizophrenia. Outside of studies of prenatal infections and risk of schizophrenia, other relevant human studies of prenatal inflammation and neurodevelopment in schizophrenia have not been reviewed. In this paper, we review human studies of 1) prenatal inflammation and risk of schizophrenia, 2) inflammation as a potential common mediator of several prenatal risk factors for schizophrenia other than prenatal infections, 3) prenatal inflammation and immune function, neurocognition, brain morphology, and gene expression in adult offspring with schizophrenia, and 4) gene by environment and gene by gene interactions relevant to these associations. We suggest future areas for human studies research based on existing findings.

Prenatal maternal infection, neurodevelopment and adult schizophrenia: a systematic review of population-based studies

BACKGROUND

Disruption of foetal development by prenatal maternal infection is consistent with a neurodevelopmental model of schizophrenia. Whether specific prenatal infections are involved, their timing and the mechanisms of any effect are all unknown. We addressed these questions through a systematic review of population-based studies.

METHOD

Electronic and manual searches and rigorous quality assessment yielded 21 studies that included an objective assessment of individual-level prenatal maternal infection and standardized psychotic diagnoses in adult offspring. Methodological differences between studies necessitated a descriptive review.

RESULTS

Results for prenatal maternal non-specific bacterial, respiratory or genital and reproductive infection differed between studies, which reported up to a two- to fivefold increased risk of schizophrenia. Evidence for herpes simplex virus type 2 (HSV-2) and Toxoplasma gondii was mixed; some studies reported up to a doubling of schizophrenia risk. Prenatal HSV-1 or cytomegalovirus (CMV) infections were not associated with increased risk. Exposure to influenza or other infections during early pregnancy may be more harmful than later exposure. Increased proinflammatory cytokines during pregnancy were also associated with risk. Prenatal infection was associated with structural and functional brain abnormalities relevant to schizophrenia.

CONCLUSIONS

Prenatal exposure to a range of infections and inflammatory responses may be associated with risk of adult schizophrenia. Larger samples, mediation and animal models should be used to investigate whether there is a 'sensitive period' during development, and the effects of prenatal infections on neurodevelopment. Inclusion of genetic and immunological information should help to elucidate to what extent genetic vulnerability to schizophrenia may be explained by vulnerability to infection.

Extracellular nucleic acids in maternal circulation as potential biomarkers for placental insufficiency

Since the placenta is being continuously remodeled during normal placental development, extracellular nucleic acids of both fetal and placental origin, packed into either trophoblast-derived apoptotic bodies or shedding syncytiotrophoblast microparticles, may be detected in maternal circulation during the course of normal gestation. Placental-insufficiency-related pregnancy complications have been shown to be associated with excessive placental trophoblast apoptosis and shedding of placenta debris. Recent advances in the field are reviewed with a focus on the diagnostic potential of particular molecular biomarkers and their eventual implementation in the currently used predictive and diagnostic algorithms for placental-insufficiency-related pregnancy complications.

Effect of prenatal exposure to lead on estrogen action in the prepubertal rat uterus

Lead is a widely spread environmental pollutant known to affect both male and female reproductive systems in humans and experimental animals and causes infertility and other adverse effects. The present paper investigated the effects of prenatal exposure to lead on different parameters of estrogen stimulation in the uterus of the prepubertal rat. In prenatally and perinatally exposed rats, estrogen-induced endometrial eosinophilia, endometrial stroma edema, and eosinophil migration towards the endometrium, and uterine luminal epithelial hypertrophy are enhanced while several other responses to estrogen appear unchanged. These effects may contribute to decrease in fertility following prenatal exposure to lead. The striking difference between most of these effects of prenatal exposure and the previously reported effects of chronic exposure to lead suggests that prenatal exposure to lead may neutralize the effects of chronic exposure to lead, providing partial protection of cell function against the adverse effects of chronic exposure to lead. We propose that the mechanism involved, named imprinting or cell programming, persisted through evolution as a nongenetic adaptive mechanism to provide protection against long-term environmental variations that otherwise may cause the extinction of species not displaying this kind of adaptation.