Preterm birth in women with inflammatory bowel disease – the association with disease activity and drug treatment

Abstract

Background: The inflammatory bowel diseases (IBD), Crohn’s disease (CD) and ulcerative colitis (UC) have been associated with an increased risk of preterm birth.

Material and methods: We identified all 246 singleton preterm births among women with IBD between July 2006 and December 2010 as cases and an equal number of controls with IBD from the Swedish national health registers, matched by maternal age, parity and IBD diagnosis (CD/UC). From register data and medical charts, we obtained information on reproductive history, comorbidity, disease activity and drug treatment (corticosteroids, 5-aminosalicylates, sulfasalazine, thiopurines and anti-TNF) as risk factors for preterm birth. Associations were estimated using conditional logistic regression and results were presented as odds ratios (OR) with 95% confidence intervals (CI).

Results: Previous preterm birth was more common among cases, OR 6.13 (95%CI: 2.51–15.01). Significant activity at any time during pregnancy (OR: 2.20; 95%CI: 1.37–3.53), and in particular both in early and in late pregnancy, was more common for cases (OR: 4.78 95%; CI: 2.10–10.9). The OR for immunosuppressive treatment with thiopurines or anti-TNF was 1.88 (1.04–3.39) without significant activity and 12.78 (95%CI: 3.68–44.72) with. The risk for women who discontinued thiopurines was 6.56 (1.44–29.82).

Conclusions: Significant activity and immunosuppressive treatment was associated with preterm birth, particularly in women with both. The existing recommendations to aim at maintaining quiescent disease during pregnancy, even if it means continuing immunosuppressive treatment, are rational.

Keywords:

• IBD
• Crohn’s disease
• ulcerative colitis
• pregnancy
• preterm birth
• IBD
• inflammatory bowel disease

Acknowledgements

We thank research nurse Camilla Byström (CB) for her assistance in collecting, administrating and reviewing the medical charts.

Ethical considerations

The study was approved by the Regional Ethical Review Board at Karolinska Institutet, Stockholm, Sweden (Record number 2006/889:31 and amendments 2007/1391-32 and 2008/631-32).

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Funding

Center for Pharmacoepidemiology receives financial support from several pharmaceutical companies.