Antirheumatic medication use among pregnant women with rheumatoid arthritis: a Norwegian nationwide drug utilisation study.

OBJECTIVES

Managing rheumatoid arthritis (RA) during pregnancy requires balancing maternal health and foetal safety. This study examined the prevalence, temporal trends, utilisation patterns, and concurrent use of antirheumatic medications from preconception through the postpartum period.

METHODS

We conducted a nationwide study using Norwegian registry data (2006-2018), linking the medical birth registry with prescription and primary care records. Pregnant women with RA were identified through diagnostic codes. Dispensed prescriptions were evaluated from 9 months before the last menstrual period to 9 months after delivery. Multitrajectory models identified distinct patterns of antirheumatic medication use over time.

RESULTS

Of 769,524 pregnancies, 3732 (0.5%) occurred in women with RA. In the period around pregnancy, 52.9% used non-steroidal anti-inflammatory drugs (NSAIDs), 33.6% glucocorticoids, 17.7% pregnancy-compatible conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), 14.8% pregnancy-contraindicated csDMARDs, and 21.6% tumour necrosis factor (TNF) inhibitors. Medication use declined from 61.3% preconceptionally to 37.6%, 22.1%, and 18.9% in the first, second, and third trimesters, respectively, then increased to 53.0% postpartum. From 2008 to 2018, antirheumatic medication use increased preconceptionally (59.8%-65.7%), during pregnancy (30.6%-49.5%), and postpartum (45.1%-54.1%), mainly due to increased TNF inhibitor use. Three distinct medication use patterns emerged: (i) NSAID-dominant use prepregnancy, (ii) glucocorticoid plus pregnancy-compatible csDMARD use continuing into pregnancy; and (iii) pregnancy-contraindicated csDMARD interrupters, mostly discontinuing during pregnancy and restarting postpartum.

CONCLUSIONS

Although antirheumatic medication use increased over time, most women discontinued treatment during pregnancy and resumed it after childbirth. The 3 distinct usage patterns highlight the need for individualised counselling and close monitoring to optimise disease management.