Premium
Ultrasonographic measurement of thymus size in IUGR fetuses: a marker of the fetal immunoendocrine response to malnutrition
Author(s) -
Cromi A.,
Ghezzi F.,
Raffaelli R.,
Bergamini V.,
Siesto G.,
Bolis P.
Publication year - 2009
Publication title -
ultrasound in obstetrics and gynecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.202
H-Index - 141
eISSN - 1469-0705
pISSN - 0960-7692
DOI - 10.1002/uog.6320
Subject(s) - perimeter , fetus , medicine , gestational age , gestation , intrauterine growth restriction , endocrinology , ultrasound , pregnancy , obstetrics , biology , genetics , geometry , mathematics , radiology
Objective To test the hypothesis that intrauterine growth restriction (IUGR) is associated with decreased thymus size in the human fetus. Methods The thymus perimeter was measured in 60 consecutive IUGR fetuses at prenatal ultrasound examination. IUGR was defined as an abdominal circumference (AC) <5 th centile. Sixty controls were identified by selection of the next consecutive appropriately grown fetus of similar gestational age (±1 week). To exclude fetal size effects, ratios between thymus perimeter and fetal biometry measurements including biparietal diameter (BPD), AC and femur length (FL), as well as estimated fetal weight (EFW) were compared between IUGR fetuses and controls. Results The proportion of fetuses with thymus perimeter <5 th centile for gestation was significantly higher in IUGR fetuses than in controls (58/60 vs. 7/60, P < 0.0001). The mean thymus perimeter/BPD ratio (0.87 ± 0.20 vs. 1.13 ± 0.13, P < 0.0001), thymus perimeter/AC ratio (0.28 ± 0.06 vs. 0.35 ± 0.03, P < 0.0001), thymus perimeter/FL ratio (1.18 ± 0.26 vs. 1.51 ± 0.19, P < 0.001) and thymus perimeter/EFW ratio (0.05 ± 0.01 vs. 0.06 ± 0.01, P = 0.02) were significantly lower in IUGR fetuses than in controls. There was a significant positive correlation between the observed‐to‐expected mean for gestation thymus perimeter ratio and the enrolment‐to‐delivery interval ( r = 0.44, P < 0.001). Conclusion IUGR is associated with a disproportionately small thymus. This supports the hypothesis that thymic involution may be part of the fetal neuroendocrine response to intrauterine starvation. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.