Pregnant Women With IBD Are More Likely to be Adherent to Biologic Therapies Than Other Medications

Sangmin Lee; Cynthia H. Seow; Kamala Adhikari; Amy Metcalfe


Aliment Pharmacol Ther. 2020;51(5):544-552. 

In This Article

Abstract and Introduction


Background: There are differences in the efficacy and safety profiles of medications used to treat IBD that may impact a woman's perceived risk of medication exposure during pregnancy, potentially leading to medication non-adherence, poor disease-control and adverse pregnancy outcomes.

Aim: To assess whether medication adherence patterns differ by drug class during pregnancy and influence birth outcomes for women with IBD.

Methods: Of 143 491 women, a validated case definition was used to identify 370 women with IBD in five administrative health databases in Alberta, Canada (2012–2015). Women who had ≥2 consecutive medications prescription for maintenance therapy for IBD in the year prior to pregnancy were included (n = 230). Prescription-based medication possession ratio ≥0.8 defined adherence. Chi-squared tests were used to compare adherence patterns by drug class and outcomes.

Results: Of the 159/230 women who were adherent during the year prior to pregnancy, 20 (12.6%; 95% CI: 8.2%, 18.8%) were not adherent and 21 (13.2%; 95% CI: 8.7%, 19.5%) discontinued their medications during pregnancy. Medication adherence during pregnancy differed significantly by drug class. A greater proportion of women on biologics (41.5%; 95% CI 32.9%, 50.7%) were adherent during pregnancy than women on thiopurines (22.9%; 95% CI 16.1%, 31.5%; P = 0.006); adherence was not significantly different for 5-aminosalicylates (35.6%; 95% CI 27.4%, 44.8%; P = 0.204). Women were more likely to be adherent to biologics (49.3%, 95% CI 37.3%, 61.3%) than thiopurines (20.9%; 95% CI 12.6%, 32.6%; P = 0.014) and 5-aminosalicylates (29.9%; 95% CI 19.9%, 42.1%; P = 0.030) in the first trimester. This was similar in the third trimester. In the second trimester, adherence pattern did not significantly differ by drug class (biologics vs thiopurines: P = 0.348; biologics vs 5-aminosalicylate: P = 0.999). Infants born to women with IBD (adherent: RR 1.58. 95% CI 1.02, 2.27; non-adherent: RR 1.32, 95% CI 0.97, 1.81) were more likely to be admitted into the neonatal intensive care unit than the general obstetric population, but this was not significantly different between women who were adherent or not adherent to their IBD medication (P = 0.711).

Conclusion: Almost a quarter of women with IBD who were previously adherent to medical therapy were not adherent during pregnancy. Adherence pattern differed by drug class.


An estimated 0.7% of the Canadian population is affected by IBD, consisting of Crohn's disease (CD) and ulcerative colitis (UC).[1] IBD, an immune-mediated chronic disease, is characterised by unpredictable cycles of disease remission and disease relapse (ie, disease flares).[2] Medical management is important in inducing and maintaining remission.[2] Tight control of IBD, which includes the use of medication, reduces the risk of disease flare and improves patients' quality of life.[2–4] Maintenance therapy for patients with IBD is typically prescribed as mono- or poly-therapy. These medications include daily oral medications (ie, 5-aminosalicylates, thiopurines), rectally administered topical medications (in the form of enemas or suppositories), weekly injections of methotrexate and/or scheduled infusions or subcutaneous injections of biologic therapies (eg, infliximab, adalimumab, golimumab, certolizumab pegol, vedolizumab and ustekinumab).[5,6]

With a recent increase in paediatric-onset of IBD and an existing peak incidence of the disease occurring during the childbearing years (ie, between 18 and 35 years of age), management of IBD prior to and during pregnancy will become an increasingly common scenario.[1,7,8] Disease activity influences maternal and foetal outcomes in women with IBD; women with active disease at the time of conception and during pregnancy are at an increased risk of adverse pregnancy outcomes, including preterm birth, small-for-gestational age, stillbirth and miscarriage.[9,10] In keeping with this, the Toronto Consensus Statements for the Management of Inflammatory Bowel Disease in Pregnancy recommend continuation of maintenance medical therapy throughout pregnancy to maintain disease remission with the exception of methotrexate, a known teratogen.[6,11]

Women are often concerned about potential teratogenic effects of their medications; however, these risks are overestimated by most pregnant women.[12,13] A survey completed by women with IBD demonstrated that while 84% were concerned about the impact of IBD medications on pregnancy, only 19% were concerned about the impact of disease activity on pregnancy.[14] Additionally, 31.6% of women had negative views on the use of IBD medications during pregnancy and believed that IBD medications were "bad" for the foetus.[15] In a survey of 145 women, 25% reported that they would rather tolerate the symptoms of IBD, such as abdominal pain and frequent diarrhoea, rather than expose the foetus to IBD medications.[15] Due to these misconceptions about IBD medications, women may completely stop taking their medications during pregnancy or take a lower dosage of medication than prescribed. Both of these situations increase the risk of disease flare, which is an independent risk factor of adverse maternal and foetal outcomes.[6] As each class of IBD medications has a unique adverse effect profile, this could lead to a divergent risk perception of each IBD drug class. Therefore, we assessed whether the medication adherence pattern differed by drug class during pregnancy for women with IBD. Furthermore, we assessed the impact of medication adherence patterns on pregnancy outcomes for women with IBD.