Polypharmacy during pregnancy and associated risk factors: a retrospective analysis of 577 medication exposures among 1.5 million pregnancies in the UK, 2000-2019

Anuradhaa Subramanian, Amaya Azcoaga-Lorenzo, Astha Anand, Katherine Phillips* (Corresponding Author), Siang Ing Lee, Neil Cockburn, Adeniyi Francis Fagbamigbe, Christine Damase-Michel, Christopher Yau, Colin McCowan, Dermot O'Reilly, Gillian Santorelli, Holly Hope, Jonathan I Kennedy, Kathryn M Abel, Kelly-Ann Eastwood, Louise Locock, Mairead Black, Maria Loane, Ngawai MossRachel Plachcinski, Shakila Thangaratinam, Sinead Brophy, Utkarsh Agrawal, Zoe Vowles, Peter Brocklehurst, Helen Dolk, Catherine Nelson-Piercy, Krishnarajah Nirantharakumar, MuM-PreDiCT Group

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)
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BACKGROUND: The number of medications prescribed during pregnancy has increased over the past few decades. Few studies have described the prevalence of multiple medication use among pregnant women. This study aims to describe the overall prevalence over the last two decades among all pregnant women and those with multimorbidity and to identify risk factors for polypharmacy in pregnancy.

METHODS: A retrospective cohort study was conducted between 2000 and 2019 using the Clinical Practice Research Datalink (CPRD) pregnancy register. Prescription records for 577 medication categories were obtained. Prevalence estimates for polypharmacy (ranging from 2+ to 11+ medications) were presented along with the medications commonly prescribed individually and in pairs during the first trimester and the entire pregnancy period. Logistic regression models were performed to identify risk factors for polypharmacy.

RESULTS: During the first trimester (812,354 pregnancies), the prevalence of polypharmacy ranged from 24.6% (2+ medications) to 0.1% (11+ medications). During the entire pregnancy period (774,247 pregnancies), the prevalence ranged from 58.7 to 1.4%. Broad-spectrum penicillin (6.6%), compound analgesics (4.5%) and treatment of candidiasis (4.3%) were commonly prescribed. Pairs of medication prescribed to manage different long-term conditions commonly included selective beta 2 agonists or selective serotonin re-uptake inhibitors (SSRIs). Risk factors for being prescribed 2+ medications during the first trimester of pregnancy include being overweight or obese [aOR: 1.16 (1.14-1.18) and 1.55 (1.53-1.57)], belonging to an ethnic minority group [aOR: 2.40 (2.33-2.47), 1.71 (1.65-1.76), 1.41 (1.35-1.47) and 1.39 (1.30-1.49) among women from South Asian, Black, other and mixed ethnicities compared to white women] and smoking or previously smoking [aOR: 1.19 (1.18-1.20) and 1.05 (1.03-1.06)]. Higher and lower age, higher gravidity, increasing number of comorbidities and increasing level of deprivation were also associated with increased odds of polypharmacy.

CONCLUSIONS: The prevalence of polypharmacy during pregnancy has increased over the past two decades and is particularly high in younger and older women; women with high BMI, smokers and ex-smokers; and women with multimorbidity, higher gravidity and higher levels of deprivation. Well-conducted pharmaco-epidemiological research is needed to understand the effects of multiple medication use on the developing foetus.

Original languageEnglish
Article number21
Number of pages13
JournalBMC medicine
Issue number1
Early online date16 Jan 2023
Publication statusPublished - 16 Jan 2023

Bibliographical note

Not applicable.

This work was funded by the Strategic Priority Fund “Tackling multimorbidity at scale” programme [grant number MR/W014432/1] delivered by the Medical Research Council and the National Institute for Health Research in partnership with the Economic and Social Research Council and in collaboration with the Engineering and Physical Sciences Research Council. BT was funded by the National Institute for Health Research (NIHR) West Midlands Applied Research Collaboration. AA, KP and SIL were funded as NIHR Academic Clinical Fellows. The views expressed are those of the authors and not necessarily those of the funders, the NIHR or the UK Department of Health and Social Care. The funders had no role in the study design, data collection and analysis, decision to publish or preparation of the manuscript.


  • Multiple medications
  • Polypharmacy
  • Medications
  • Prescriptions
  • Pregnancy
  • Multimorbidity
  • Multiple long-term conditions


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