INTRODUCTION: We investigated the reliability of fetal thymus measurement during first-trimester screening, and associated fetal thymus size with crown-rump length, @entity66 and fetal outcome. MATERIAL AND METHODS: In a retrospective cohort of 971 normal singleton first-trimester fetuses, we measured the anterior-posterior diameter of the thymus in a midsagittal plane in 767 fetuses. The intra-observer and inter-observer reliabilities were tested by intra-class correlation coefficient. We correlated thymus size with fetal crown-rump length, and investigated its association with @entity66 ( @entity6 , @entity627 , @entity101 and @entity3459 ) and fetal outcome (small for gestational age, @entity600 and umbilical artery pH) using regression analyses. RESULTS: The intra-observer and inter-observer reliabilities of fetal thymus measurement were excellent (intra-class correlation coefficient 0.926, 95% CI 0.745-0.981 and 0.945, 95% CI 0.886-0.993, respectively). A linear relationship was found between crown-rump length and thymus size (b = 0.023, p = 0.001). Pregnancies affected by @entity6 had a decreased fetal thymus size (b = -0.209, p = 0.001), whereas in pregnancies affected by maternal @entity627 the thymus size was increased (b = 0.285, p < 0.001). Fetal thymus size was not associated with maternal @entity101 or @entity3459 . There was a positive association between @entity600 and fetal thymus size (p < 0.001). CONCLUSION: Measurement of first-trimester thymus size is reliable. Fetal thymus size has a linear correlation with crown-rump length. @entity6 , @entity627 and @entity600 appear to have an association with fetal thymus size.

Assessment of first-trimester thymus size and correlation with XXXX and fetal outcome.

@entity627 :: ('MESH:D012216', 'Disease') :: ['rheumatic disease', 'rheumatic disorders'] @entity101 :: ('MESH:D006973', 'Disease') :: ['hypertension'] @entity66 :: ('MESH:D004194', 'Disease') :: ['maternal diseases'] @entity6 :: ('MESH:D003920', 'Disease') :: ['Maternal diabetes', 'diabetes mellitus', 'maternal diabetes'] @entity600 :: ('MESH:D000014', 'Disease') :: ['preterm birth'] @entity3459 :: ('MESH:D025861', 'Disease') :: ['coagulation disorders', 'maternal coagulation disorders']
@entity66 :: (MESH:D004194,Disease) :: ['maternal diseases']
