Prescription Drug Use in Pregnancy: A Retrospective, Population-Based Study in British Columbia, Canada (2001–2006)

Daw, Jamie R.; Mintzes, Barbara; Law, Michael R.; Hanley, Gillian E.; Morgan, Steven G.

doi:10.1016/j.clinthera.2011.11.025

« Previous Next »Clinical Therapeutics
Volume 34, Issue 1 , Pages 239-249.e2, January 2012

Prescription Drug Use in Pregnancy: A Retrospective, Population-Based Study in British Columbia, Canada (2001–2006)

The data in this article were presented in oral form at the Canadian Association for Health Services and Policy Research Annual Conference, Toronto, Ontario, Canada, May 10–13, 2010; and Innovations in Gender, Sex, and Health Research, Toronto, Ontario, Canada, November 22–23, 2010.

Jamie R. Daw, MSc
- Centre for Health Services and Policy Research, School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada
Barbara Mintzes, PhD
- Centre for Health Services and Policy Research, School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
Michael R. Law, PhD
- Centre for Health Services and Policy Research, School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada
Gillian E. Hanley, PhD
- Centre for Health Services and Policy Research, School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada
Steven G. Morgan, PhD
- Centre for Health Services and Policy Research, School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada
- Address correspondence to: Steven G. Morgan, PhD, Centre for Health Services and Policy Research, School of Population and Public Health, University of British Columbia, 201-2206 East Mall, Vancouver, BC, V6T1Z3, Canada

Accepted 17 November 2011. published online 15 December 2011.

Abstract

Background

Owing to the paucity of evidence available on the risks and benefits of drug use in pregnancy, the use of prescription medicines is a concern for both pregnant women and their health care providers.

Objective

The aim of this study was to measure the frequency, timing, and type of medicines used before, during, and after pregnancy in a Canadian population.

Methods

This retrospective cohort analysis used population-based health care data from all pregnancies ending in live births in hospitals in British Columbia from April 2001 to June 2006 (n = 163,082). Data from hospital records were linked to those in outpatient prescription-drug claims. Data from prescriptions filled from 6 months before pregnancy to 6 months postpartum were analyzed. Drugs were classified by therapeutic category and US Food and Drug Administration (FDA) pregnancy risk categories.

Results

Prescriptions were filled in 63.5% of pregnancies. Evidence on safety is limited for many of the medicines most frequently filled in pregnancy, including codeine, salbutamol, and betamethasone. At least 1 prescription for a category D or X medicine was filled in 7.8% of pregnancies (5.5% category D; 2.5% category X). The most frequently filled prescriptions for category D drugs were benzodiazepines and antidepressants. The most frequently filled prescriptions for category X drugs were oral contraceptives and ovulation stimulants filled in the first trimester.

Conclusions

The majority of pregnant women in British Columbia filled at least 1 prescription, and ∼1 in 13 filled a prescription for a drug categorized as D or X by the FDA. The prevalence of maternal prescription drug use emphasizes the need for postmarketing evaluation of the risk–benefit profiles of pharmaceuticals in pregnancy. Future research on prenatal drug use based on administrative databases should examine maternal treatment adherence and the determinants of maternal drug use, considering maternal health status, sociodemographics, and the characteristics and providers of prenatal care.

Key words: data linkage , pregnancy , prescription drugs , teratogens