Özet:

Objective: The purpose of this study was to analyze the fetal thymus size by sonography in healthy, small for gestational age (SGA), and fetal growth restriction (FGR) pregnancies and investigate if there is a difference between healthy fetuses and those with growth restriction. Study Design: The thymic-thoracic ratio (TTR), transverse diameter, and perimeter of the fetal thymus were prospectively measured in SGA and FGR pregnancies between the gestational ages of 20 and 37 weeks and compared with healthy controls. Fetal abdominal circumference (AC) or estimated fetal weight (EFW) <10th percentile for gestational age was defined as SGA, and <3rd percentile was defined as FGR. FGR pregnancies were further divided based on normal or abnormal Doppler assessment. Results: 128 FGR, 34 SGA, and 162 healthy pregnancies were enrolled in the study. All measurements of the fetal thymus were significantly lower in the FGR group (p<0.05). Among growth-restricted fetuses, thymus size was smallest in those with abnormal Doppler flow (p<0.05). The TTR values of those in the normal doppler and SGA groups were significantly lower than those in the control group (p<0.05). Conclusion: FGR is associated with a small fetal thymus, which appears to be correlated with the severity of the growth restriction. Among FGR fetuses, a smaller thymus was related to abnormal fetal Doppler values.