Disease course and obstetric outcomes of pregnancies in juvenile idiopathic arthritis: are there any differences among disease subtypes? A single-centre retrospective study of prospectively followed pregnancies in a dedicated pregnancy clinic

To study disease activity during pregnancy and obstetric outcomes in patients with juvenile idiopathic arthritis (JIA) upon different subsets and with focus on medication use. Retrospective observational study of 22 pregnancies in 16 JIA patients (95.5% Caucasian) who were followed between 2010 and 2018. Disease activity, flares and medications were recorded before conception, during each trimester and postpartum period. Pregnancies occurred in 10 (45.5%) oligoarticular extended (OLA-E), 6 (27.3%) in polyarticular (PLA), 4 in (18.2%) systemic (SYS), 1 (4.5%) in oligoarticular persistent (OLA-P) and 1 (4.5%) in enthesitis-related arthritis (ERA) JIA patients. The median age at disease diagnosis and at conception was 5.5 and 28 years (respectively). The median disease duration was 20 years. Nineteen (95%) pregnancies started in a period of stable disease remission. Among the 22 pregnancies, 20 ended with a live birth (90.9%). No spontaneous miscarriages occurred; two voluntary interruption of pregnancy were performed. There were 7 flares in 6/20 pregnancies (35%) and 8 flares (8/22, 36.4%) occurred in postpartum period, all of them in OLA-E and PLA patients. Seven patients (35%) were taking biological disease-modifying anti-rheumatic drugs (bDMARDs) at conception, and 6 of them stopped this treatment at positive pregnancy test. Five patients resumed bDMARDs either during pregnancy (3 exposed during the third trimester) or puerperium due to a flare. Four preterm deliveries (20%) were recorded, all in patients who had a flare during pregnancy. The preconception counselling should include the evaluation of disease subset, as OLA-E and PLA may flare more than other subsets, especially if bDMARDs are discontinued at positive pregnancy test. Continuation of bDMARDs during pregnancy should be considered to minimize the risk of adverse pregnancy outcomes, particularly preterm delivery.• In our cohort, all the flares during pregnancy and 75% of postpartum flares were observed in patients who withdrew bDMARDs and cDMARDs at the beginning of pregnancy.• Flares were observed only in PLA and OLA-E patients.• Preterm delivery occurred in 20% of the pregnancies; all of these patients had a disease flare during pregnancy.