Pregnancy outcomes in 1869 pregnancies in a large cohort from the Spanish Society of Rheumatology Lupus Register (RELESSER)

INTRODUCTION:Obstetric complications are more common in women with systemic lupus erythematosus (SLE) than in the general population. OBJECTIVE:To assess pregnancy outcomes in women with SLE from the RELESSER cohort after 12 years of follow-up. METHODS:A multicentre retrospective observational study was conducted. In addition to data from the RELESSER register, data were collected on obstetric/gynaecological variables and treatments received. The number of term pregnancies was compared between women with pregnancies before and after the diagnosis of SLE. Further, clinical and laboratory characteristics were compared between women with pregnancies before and after the diagnosis, on the one hand, and with and without complications during pregnancy, on the other. Bivariate and multivariate analyses were carried out to identify factors potentially associated with complications during pregnancy. RESULTS:A total of 809 women were included, with 1869 pregnancies, of which 1395 reached term. Women with pregnancies before the diagnosis of SLE had more pregnancies (2.37 vs 1.87) and a higher rate of term pregnancies (76.8% vs 69.8%, p < 0.001) compared to those with pregnancies after the diagnosis. Women with pregnancies before the diagnosis were diagnosed at an older age (43.4 vs 34.1 years) and had more comorbidities. No differences were observed between the groups with pregnancies before and after diagnosis in antibody profile, including anti-dsDNA, anti-Sm, anti-Ro, anti-La, lupus anticoagulant, anticardiolipin or anti-beta-2-glycoprotein. Overall, 114 out of the 809 women included in the study experienced complications during pregnancy, including miscarriage, preeclampsia/eclampsia, foetal death, and/or preterm birth. Women with complications had higher rates of antiphospholipid syndrome (40.5% vs 9.9%, p < 0.001) and higher rates of positivity for IgG anticardiolipin (33.9% vs 21.3%, p = 0.005), IgG anti-beta 2 glycoprotein (26.1% vs 14%, p = 0.007), and IgM anti-beta 2 glycoprotein (26.1% vs 16%, p = 0.032) antibodies, although no differences were found regarding lupus anticoagulant. Among the treatments received, only heparin was more commonly used by women with pregnancy complications. We did not find differences in corticosteroid or hydroxychloroquine use. CONCLUSIONS:The likelihood of term pregnancy is higher before the diagnosis of SLE. In our cohort, positivity for anticardiolipin IgG and anti-beta-2- glycoprotein IgG/IgM, but not lupus anticoagulant, was associated with a higher risk of poorer pregnancy outcomes.