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Effects of Medication Use in Pregnancy on Infant Neurodevelopment

Periodic Reporting for period 4 - DrugsInPregnancy (Effects of Medication Use in Pregnancy on Infant Neurodevelopment)

Período documentado: 2020-03-01 hasta 2021-08-31

The background for the DrugsInPregnancy project is the current lack of knowledge about potential long-term effects of prenatal exposure to medications on the child’s brain. Currently, thousands of pregnant women in the EU and worldwide are being prescribed medications for which we do not have sufficient information on fetal safety. The lack of knowledge stands in disturbing contrast to the frequent use of analgesics and psychotropic medications, and the public demand for information about the long-term safety on the child’s developing brain. We believe that our current understanding of safety pharmacology is oversimplified and that medication prescribed during pregnancy may play an unrecognized role in the development of neurodevelopmental disorders. The precise molecular mechanisms of most teratogenic processes are unknown but altered patterns of DNA methylation, which result in aberrant gene expression, are thought to play a vital role. With the recent juncture between availability/affordability of genome-wide mapping of DNA methylation, the DrugsInPregnancy project has just come within reach.
Due to ethical considerations, pregnant women cannot be included in randomized controlled trials. As learned from the thalidomide catastrophe, results from animal studies cannot be directly extrapolated to humans and the structure or activity of the drug is generally not predictive of teratogenesis. Therefore, prospective, long-term pharmacoepidemiological studies among pregnant women offer the only real solution to fill the gap of knowledge concerning safety of pharmaceuticals in pregnancy.
The aim of DrugsInPregnancy is to determine how specific medication groups including antidepressants, benzodiazepines and several groups of analgesics may act on the child’s developing brain from both dimensional and diagnosis perspectives. Moreover, the aim is to determine whether there are epigenetic mechanisms involved in human drug neurotoxicity. In this project, we have the unique opportunity to use several population-based registries and a population-based birth cohort including over 100,000 mother-child pairs and biological data (DNA samples from umbilical cord blood) to study how medications may act on the offspring. The size and richness of the available human data in this project makes this project unique.
In the DrugsInPregnancy project, we have linked epidemiological data from the birth cohort and national registries. Cord blood samples for a pharmacoepigenetic study on paracetamol have been analysed. We have performed studies specifically assessing different aspects of data quality and availability of advanced methods for confounding control within reproductive pharmacoepidemiology. Our work has raised important debates on how child neurodevelopmental disorders and delays should be detected, and how DNA-methylation analysis using cord blood should be correctly performed. We advocate that use of advanced methods for confounding control, handling of missing data, use of longitudinal methods for modelling medication exposures and methods for adjusting for time-varying confounders will enable improved causal inference about effects of prenatal exposure to medications on human neurodevelopment. We argue that psychometric instruments and diagnoses of developmental disorders have different strengths and weaknesses and will supplement each other, and that without correction for cell type composition in studies on DNA-methylation erroneous conclusions will be made.
In this project, we found no substantial increased risk for ADHD diagnosis, externalizing, emotional, or social problems in preschool-aged children following prenatal SSRI-antidepressant exposure, beyond that posed of the maternal underlying illness. We found a slightly elevated risk of ADHD diagnosis after exposure to opioids for 5 or more weeks during fetal life. Taken together, the results from several studies on benzodiazepines and/or z-hypnotics were reassuring. Our findings suggested no increased risk of ADHD diagnosis, child fine motor problems, externalizing and internalizing problems at 5 years of age after prenatal exposure to benzodiazepines and/or z-hypnotics. Residual confounding by indication and/or a higher drug dose regimen among women with anxiety/depression may explain a moderate association of gross motor and communication deficits with late-pregnancy benzodiazepine/z-hypnotic use.
We have found that prenatal exposure to low doses paracetamol is associated with reduced risk of ADHD, whereas high doses increases risk of ADHD in offspring. We have demonstrated that there may be a link between use of high doses paracetamol among children with ADHD and altered DNA-methylation patterns.
Balancing on the cutting-edge between pharmacoepidemiology and epigenetics, the DrugsInPregnancy project represents a true shift in paradigm by focusing on medication safety and the developing brain, and by following over 100 000 children from the womb into adolescence. Our findings are the first in the world to suggest that in children with ADHD, prenatal long-term exposure to paracetamol is associated with changes in the DNA methylation pattern in cord blood compared to non-exposed controls. As this was not confirmed in a replication study, we were able to identify the different microarrays used as the reason for the discrepancy in findings.
We provide guidelines for researchers regarding how to perform studies on long-term neurodevelopmental outcomes in children, and demonstrate how school test results can be used to measure scholastic skills in perinatal pharmacoepidemiological studies.
We advocate that genetic vulnerability to drug neurotoxicity needs to be considered, and propose to use family designs as well as polygenic risk scores to address genetic confounding. The DrugsInPregnancy project has demonstrated the need to create a pipeline for complete -omics integration of genetic, epigenetic and epidemiological data capitalizing on recent advances within computational sciences. In particular, by using machine learning to turn complex epidemiological, genetic and clinical data into testable hypotheses, we will be able to facilitate scientific discovery of novel genetic and clinical risk factors for drug toxicity and adverse pregnancy outcomes in the near future.
The DrugsInPregnancy project has provided us with a deeper understanding of effects of prenatal exposure to analgesics and psychotropics on DNA-methylation and neurodevelopmental disorders in offspring. The findings and recommendations provided by the project will improve the scientific quality of future perinatal pharmacoepidemiology and drive the field of pharmacoepigenetic forward in a more scientifically robust way. We expect that the implications will not only be important for how we treat pregnant women, but for how we understand epigenetic mechanisms of human drug neurotoxicity.