Preconception clinical factors related to adverse pregnancy outcomes in patients with systemic lupus erythematosus or primary Sjögren’s syndrome: a retrospective cohort study

OBJECTIVE: To identify preconception clinical factors associated with adverse pregnancy outcomes (APO) in patients with systemic lupus erythematosus (SLE) or primary Sjögren’s syndrome (pSS). METHODS: A single-centre, retrospective cohort study was conducted, which included pregnant women treated at the University Medical Center Groningen between January 2010 and August 2021 who fulfilled classification criteria for SLE or pSS. Demographic data, relevant comorbidities, disease duration, disease activity before and during pregnancy, APO, laboratory parameters and treatment regimens were recorded. Associations between the presence of APO and preconception characteristics were evaluated. RESULTS: Our study population included 48 (70%) SLE and 21 (30%) pSS pregnancies concerning 70 fetuses (one twin). Preterm birth (n=9, 19%) was the most frequent APO in SLE pregnancies, while in pSS pregnancies this was miscarriages (n=3, 14%). There were no associations between the presence of APO in SLE pregnancies and clinical parameters, laboratory parameters or medication use prior to conception. In the pSS group, significant associations were found between the presence of APO and body mass index (p=0.010), parity (p=0.046), C4 (p=0.021) and low C4 levels (p=0.002). CONCLUSIONS: No preconception risk factors related to APO were found in SLE pregnancies, whereas preconception complement levels were associated with APO development in patients with pSS.