Antinuclear antibodies in women with recurrent early pregnancy loss: prevalence and impact on subsequent pregnancy outcome

Research question: What is the prevalence of antinuclear antibodies (ANA) in women with recurrent early pregnancy loss (REPL), and do they affect subsequent pregnancy outcome? Design: This single-centre, retrospective cohort study included 960 women consulting for REPL between January 2014 and December 2019. REPL was defined as ≥2 pregnancy losses before 10 weeks’ gestation, including natural and autologous IVF/intracytoplasmic sperm injection pregnancies. ANA testing via indirect immunofluorescence on HEp-20-10 cells was part of routine evaluation. Confirmed systemic autoimmune diseases, uterine anomalies, parental chromosomal abnormalities, uncontrolled endocrine disorders and age ≥40 years were exclusion criteria. ANA prevalence and its association with subsequent pregnancy outcomes were assessed. The primary outcome was early pregnancy loss (EPL); secondary outcomes were biochemical pregnancy loss, clinical miscarriage and live birth rates. Results: ANA screening of ≥1:80 was observed in 125/960 women (13.0%), comparable to the general population. No significant differences were seen in maternal age, body mass index, ethnicity or conception method between ANA-positive and ANA-negative women. The mean number of prior EPL was similar (2.7 versus 2.8, P = 0.06), but the percentage of women with thyroid antibodies was higher among ANA-positive women (21.6% versus 10.2%, P < 0.001). The subsequent EPL rate was similar (34.9% versus 40.5%, P = 0.33). Logistic regression showed no independent effect of ANA positivity for additional EPL (odds ratio 0.73, 95% CI 0.45–1.20, P = 0.22). Live birth rates were also similar (P = 0.50). Conclusions: ANA prevalence in women experiencing REPL was 13.0%, comparable to general population rates. ANA positivity did not negatively impact subsequent pregnancy outcomes. These findings do not support routine ANA testing in REPL or use of immunological add-ons based solely on ANA positivity.