Background Inflammatory rheumatic disease do have an influence on pregnancy course and outcome. There is little knowledge about the comparison between two rheumatic diseases.

Objectives To analyze pregnancy complications, pregnancy outcome and delivery mode in patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA).

Methods Patients with RA and SpA were compared with those of matched healthy controls (HC) with respect to pregnancy complications, pregnancy outcome and delivery mode. Patients and controls were prospectively followed at the University of Bern.

Results We analyzed 244 pregnancies, of which 96 pregnancies occurred in 86 RA patients, 78 in 70 SpA patients and 70 in 70 healthy women.

Pregnancy complications (gestational diabetes, preeclampsia, infection, premature rupture of membranes) were more frequent in RA patients (11.5%) and in SpA patients (17.9%) than in HC (1.4%).

Pregnancy outcome of 174 pregnancies in RA and SpA patients resulted in 178 live born infants, 6 sets of twins, one stillbirth and one induced fetal demise. The induced fetal demise was performed in a twin pregnancy on a fetus with a congenital anomaly. Congenital anomalies occurred in 6 infants (3 in RA and 3 in SpA patients). All HC had live births. Median birth weight was lower in patients compared with HC (RA: 3100g, SpA: 3245g, HC: 3455g). RA and SpA patients had more often small for gestational age infants (birth weight <10th percentile; RA: 16.2%, SpA: 11.4%, HC: 1.4%) and preterm deliveries (RA: 18.8%, SpA: 11.5%, HC: 1.4%).

With regard to delivery mode, most women had vaginal deliveries (RA: 51.0%, SpA: 57.7%, HC: 72.9%). Birth by caesarean section (elective and emergency), was more frequent in RA and SpA patients than in the healthy controls (RA: 44.8%, SpA: 39.7%, HC: 27.2%). Emergency caesarean sections were indicated in 22.9% of pregnancies among RA patients, in 21.8% of SpA patients and in 14.3% of healthy women.

Conclusions Pregnancy complications, caesarean section, and adverse child outcomes were more frequent in patients with RA and SpA compared to healthy women. However, no significant differences in pregnancy outcomes were observed between RA and SpA patients indicating comparable risks induced by the autoimmune inflammatory process.

Disclosure of Interest None declared