Objectives: To study (i) the drug utilization pattern of anti-rheumatic drugs in pregnant women and expectant fathers and (ii) the association between the use of anti-rheumatic drugs during pregnancy and the risk of congenital malformations.
Method: Pregnancies registered in the Medical Birth Registry of Norway (MBRN) were linked to the Norwegian Prescription Database (NorPD) in the period 2004-2007. Prescriptions for anti-rheumatic drugs issued to women 3 months prior to and during pregnancy and to men 3 months prior to conception were identified. Congenital malformations were recorded according to the European Surveillance of Congenital Anomalies (EUROCAT) guidelines.
Results: In 154,976 singleton pregnancies, 1461 of the women (0.9%) and 1198 (0.8%) of the known fathers (150,530) were dispensed anti-rheumatic drugs at least once during the study period: 723 had non-steroidal anti-inflammatory drugs (NSAIDs), 633 prednisolone (CS), 119 sulfasalazine (SASP), 101 azathioprine (AZA), 58 hydroxychloroquine (HQC), 37 etanercept (ETAN), eight methotrexate (MTX), two leflunomide (LEF), and three adalumimab (ADA). Odds ratios (ORs) for malformations in children born of women (w) or men (m) who had received the drugs were OR(w) = 1.06 [95% confidence interval (CI) 0.85-1.32] and OR(m) = 1.19 (95% CI 0.93-1.51), respectively, and for major malformation OR(w) = 1.05 (95% CI 0.79-1.40) and OR(m) = 1.26 (95% CI 0.93-1.71), respectively. None of the children whose mother had received MTX, LEF, ETAN, or ADA were reported to be born with major malformations.
Conclusions: This study revealed no major malformations of the alert drugs MTX, LEF, ETAN, or ADA. Although the numbers are limited, this provides important population-based information to both expectant parents and prescribers.