Assessment of fetal thymus size in pregnant women with rheumatic diseases: A case–control study

Abstract

AbstractPurposeTo investigate the fetal thymic‐thoracic ratio (TT‐ratio) in pregnancies diagnosed with rheumatoid arthritis (RA) and ankylosing spondylitis (AS).MethodsThirty‐two pregnant women with rheumatic disease and 96 low‐risk pregnant women between 20 and 37 weeks were included in the study. Three control patients were randomly selected for each study patient. TT‐ratio was calculated by measuring the anterior–posterior diameter of the thymus and the intrathoracic mediastinal diameter. Data were compared between the study group, including RA and AS, and the control group.ResultsThirty‐two pregnant women with arthritis, 19 diagnosed with RA and 13 with AS, were evaluated. The mean value of the study group TT‐ratio was 0.33; control group, 0.36; a statistically significant difference was found (p < 0.001). Perinatal outcomes were not different when compared with control patients. There was a negative correlation between disease duration, maternal C‐reactive protein, erythrocyte sedimentation rate, and TT‐ratio.ConclusionThis is the first study to prospectively evaluate the fetal TT‐ratio in patients with RA and AS. Systemic inflammation appears to affect fetal thymus size. Appropriate management of maternal rheumatic diseases is essential for developing the thymus, a vital immune system component.