Background The risk of congenital malformations in offspring of men with inflammatory joint diseases (IJD) treated with disease modifying antirheumatic drugs (DMARDs) before conception is largely unknown.
Objectives To study the occurrence of severe malformations in offspring of male patients with IJD exposed to DMARDs within 3 months before conception compared with references from the general population.
Methods The national identification numbers of both the mother and the father of the newborn are registered in the Medical Birth Registry of Norway (MBRN). Linkage of data from a longitudinal observational study of IJD patients (NOR-DMARD) and the MBRN enabled to study potential associations of severe congenital malformation in offspring after paternal exposure to DMARDs within 3 months of conception compared to deliveries from the general population. Births in the period 2000-2011 were analyzed. Potential associations were assessed by logistic regression analysis with adjustments for maternal and paternal age at delivery and for year of birth and presented as adjusted odds ratios with corresponding 95% confidence intervals. The birth defects included severe malformations in any organ system. The definition of severe malformations in MBRN is in accordance with the European Registration of Congenital Anomalies (EUROCAT) (1). All severe congenital anomalies were grouped together as one entity.
Results Among 3866 male IJD patients there were 110 paternal pre-conception DMARD exposed births. The distribution of pre-conception synthetic and biological DMARDs among the 110 births were as follows: TNF-α inhibitors as monotherapy 33%, TNF-α inhibitors in combination with methotrexate (MTX) 19%, MTX monotherapy or in combinations with other synthetic DMARDs 25%, sulfasalazine 15%, other medications (leflunomide, azathioprine, hydroxychloroquine) 7%. The dose of MTX ranged between 12.5-20 mg weekly.
Conclusions Preconception paternal exposure to DMARDs was not associated with increase in adverse outcomes of pregnancy.
European Surveillance of Congenital Anomalies, EUROCAT Guide 1.3, chapter 3.3: Coding of EUROCAT subgroups of congenital anomalies. Available from: www.eurocat-network.eu/
Disclosure of Interest None declared