P-Glycoprotein-Mediated Drug Interactions in Pregnancy and Changes in the Risk of Congenital Anomalies: A Case-Reference Study

Daud, A. N. A., Bergman, J. E. H., Bakker, M. K., Wang, H., Kerstjens-Frederikse, W. S., de Walle, H. E. K., Groen, H., Bos, J. H. J., Hak, E. & Wilffert, B., 2-Jul-2015, In : Drug Safety. 38, 7, p. 651-659 9 p.

Research output: Contribution to journalArticleAcademicpeer-review

INTRODUCTION: Drug use in pregnancy is very common but may cause harm to the fetus. The teratogenic effect of a drug is partly dependent on the drug level in the fetal circulation, which is associated with the transport across the placenta. Many drugs are substrates of P-glycoprotein (P-gp), an efflux transporter that acts as a protective barrier for the fetus. We aim to identify whether drug interactions associated with P-gp promote any changes in fetal drug exposure, as measured by the risk of having children with congenital anomalies.

METHODS: In this study, cases (N = 4634) were mothers of children with congenital anomalies registered in the EUROCAT Northern Netherlands registry, and the reference population were mothers of children (N = 25,126) from a drug prescription database (

RESULTS: Drugs that are associated with P-gp transport were commonly used in pregnancy in cases (10 %) and population (12 %). Several drug classes, which are substrates for P-gp, were shown to have a higher user rate in mothers of cases with specific anomalies. The use of this subset of drugs in combination with other P-gp substrates increased the risk for specific anomalies (odds ratio [OR] 4.17, 95 % CI 1.75-9.91), and the addition of inhibitors further increased the risk (OR 13.03, 95 % CI 3.37-50.42). The same pattern of risk increment was observed when the drugs were analyzed separately according to substrate specificity.

CONCLUSIONS: The use of drugs associated with P-gp transport was common during pregnancy. For several drug classes associated with specific anomalies, P-gp-mediated drug interactions are associated with an increased risk for those specific anomalies.

Original languageEnglish
Pages (from-to)651-659
Number of pages9
JournalDrug Safety
Issue number7
Early online date29-May-2015
Publication statusPublished - 2-Jul-2015



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