The fetal safety of thiopurines for the treatment of inflammatory bowel disease in pregnancy

Abstract

Maintaining remission of inflammatory bowel disease (IBD) during pregnancy is critical for positive pregnancy outcomes. Conflicting data exist regarding the association between thiopurine use for IBD treatment in pregnancy and adverse pregnancy outcomes and this meta-analysis aims to clarify this association. A meta-analysis was performed of all original human studies reporting outcomes in pregnancy in patients receiving thiopurines. Nine studies satisfied the inclusion criteria and a total of 494 patients with IBD and 2,782 IBD controls were reported. When compared with healthy women, those receiving thiopurines had an increased risk for congenital malformations (RR 1.45; 95% CI 1.07–1.96; p = 0.02); however, when compared with IBD controls, there was no increased risk (RR 1.37; 95% CI 0.92–2.05; p = 0.1). These data provide support for thiopurines having a minimal risk, if any, to the fetus.

Keywords::

• Azathioprine
• meta-analysis
• 6-mercaptopurine
• pregnancy

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

This study is supported by a grant from the Canadian Institutes for Health Research (CIHR). JRH is supported by a CIHR Vanier Canada Graduate Scholarship. GK is the holder of the Ivey Chair in Molecular Toxicology, The Department of Medicine, University of Western Ontario and the Research Leadership for Better Pharmacotherapy During Pregnancy and Breastfeeding, The Hospital for Sick Children.