Gaps in knowledge of pharmacokinetic changes in pregnancy and their clinical consequences

November 01, 2016

There is a substantial gap in knowledge of pharmacokinetic changes in pregnancy and their clinical consequences, according to a study published by Shinya Ito and colleagues from the Hospital for Sick Children, Toronto, Canada, in PLOS Medicine.

Pregnant women take a variety of medications, including prescription and over-the-counter medications, with more than 90% of women in some areas reporting use of at least one medication during pregnancy. However, information may not be available on whether or how to adjust dosing to compensate for the physiologic changes that occur during pregnancy.

The researchers conducted a systematic review of the biomedical literature, and identified 198 studies, involving 121 different medications, that measured changes in pharmacokinetics (absorption, distribution, metabolism, and excretion of drugs) during pregnancy and/or the resultant clinical impact of these changes. Across the different drug classes, they frequently observed a decrease in drug exposure mainly due to increased elimination. However, only a few studies described changes in clinical outcomes associated with altered pharmacokinetics during pregnancy.

The authors say: "It is essential for clinicians to be aware of these unique pregnancy -related changes in pharmacokinetics, and to critically examine their potential clinical implications."
Research Article


The authors received no specific funding for this work.

Competing Interests:

The authors have declared that no competing interests exist.


Pariente G, Leibson T, Carls A, Adams-Webber T, Ito S, Koren G (2016) Pregnancy-Associated Changes in Pharmacokinetics: A Systematic Review. PLoS Med 13(11): e1002160. doi:10.1371/journal.pmed.1002160

Author Affiliations:

Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, Toronto, Ontario, Canada
Hospital Library, Hospital for Sick Children, Toronto, Ontario, Canada
Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada


Perspective Article


LCC is supported by a National Institute for Health Research Professorship, RP-2014-05-019. AD is supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests:

AD is Director and cofounder of Magnus Growth, part of Magnus Life Science, a company that is aiming to take to market a novel treatment for fetal growth restriction.


Chappell LC, David AL (2016) Improving the Pipeline for Developing and Testing Pharmacological Treatments in Pregnancy. PLoS Med 13(11): e1002161. doi:10.1371/journal.pmed.1002161

Author Affiliations:

Women's Health Academic Centre, King's College London, London, United Kingdom
Institute for Women's Health, University College London, London, United Kingdom



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