Fetal thymic involution: a sonographic marker of the fetal inflammatory response syndrome.
OBJECTIVE
The purpose of this study was to evaluate whether there is a relationship between the sonographic fetal thymus size and the presence of an intrauterine infection in patients with preterm labor.


METHODS
Thirty-one women who had been admitted with preterm labor and intact membranes between 24 and 32 weeks of gestation were included. Fetal thymus perimeter was measured sonographically, and amniocentesis for the microbiologic assessment of the amniotic cavity was performed. Placentas and umbilical cords were examined for the presence of chorioamnionitis/funisitis.


RESULTS
The prevalence of preterm delivery and intra-amniotic infection was 51.6% (16/31 women) and 32.3% (10/31 women), respectively. In all cases with intrauterine infection and in 23.8% of cases without intrauterine infection, the fetal thymus perimeter was below the 5th percentile for gestational age (10/10 women vs 5/21 women; P < .01). Isolated histologic chorioamnionitis and funisitis were found in 22.6% and 25.8% of fetuses, respectively. The fetal thymus was below the 5th percentile for gestational age in 100%, 71.4%, and 12.5% of patients with histologic signs of funisitis and isolated chorioamnionitis and without histologic signs of infection, respectively.


CONCLUSIONS
Fetal thymus involution in preterm labor patients is strongly associated with funisitis, which is the histologic manifestation of the fetal inflammatory response syndrome.
Di Naro
Edoardo
E
Department of Obstetrics, University of Bari, Bari, Italy.
Cromi
Antonella
A
Ghezzi
Fabio
F
Raio
Luigi
L
Uccella
Stefano
S
D'Addario
Vincenzo
V
Loverro
Giuseppe
G
D001424:Bacterial Infections; D002821:Chorioamnionitis / Q000382:microbiology* / Q000473:pathology; D005260:Female; D005865:Gestational Age; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000453:epidemiology / Q000401:mortality / Q000503:physiopathology; D007752:Obstetric Labor, Premature; D011247:Pregnancy; D047928:Premature Birth; D012720:Severity of Illness Index; D013950:Thymus Gland / Q000000981:diagnostic imaging*; D016216:Ultrasonography, Prenatal