Medication use during pregnancy and pregnancy outcomes in women with immune mediated inflammatory diseases: a UK-based matched cohort study.

Abstract

Immune mediated inflammatory diseases (IMID) affect women of childbearing age, yet there is a lack of evidence about the risk of adverse pregnancy outcomes and the interaction with medication. This study aims to characterise prescribing patterns and pregnancy outcomes in women with an IMID diagnosis. Pregnancies to women with rheumatoid arthritis (RA), psoriatic arthritis (PsA), psoriasis (PsO), spondyloarthritis (SpA) and inflammatory bowel disease (IBD) were identified within the Clinical Practice Research Datalink, between 01-Jan-2000 and 31-Jun-2020, and matched to pregnancies in women with no such diagnosis. Drug prescribing patterns were described during and surrounding pregnancy. The risk of spontaneous pregnancy loss and major congenital malformations (MCMs) were evaluated compared to women without an IMID. Exposure to commonly prescribed disease-modifying anti-rheumatic drugs was evaluated. The risk of a spontaneous pregnancy loss ranged from HRadj 1.01 (CI950.79-1.28) for PsA to HRadj 1.18 (CI951.07-1.30) for IBD when compared to women without these conditions. No significant increases in the overall risk of MCMs were observed, with the exception of IBD where it reached borderline significance based on sensitivity analyses (ORadj 1.31 (CI951.00-1.71). No evidence of an increased risk of spontaneous loss was observed in women taking azathioprine, mesalazine and sulfasalazine. We found no increased risk of spontaneous loss in women with RA, PsA or SpA but a small increase in women with psoriasis or IBD. There was a borderline increased risk of all MCMs in offspring of women with IBD, which should be interpreted cautiously because of potential residual confounding.