Author response to: The relationship between sonographic fetal thymus size and the components of the systemic fetal inflammatory response syndrome in women with preterm prelabour rupture of membranes
Article first published online: 21 JAN 2009
© 2009 The Authors Journal compilation © RCOG 2009 BJOG An International Journal of Obstetrics and Gynaecology
BJOG: An International Journal of Obstetrics & Gynaecology
Volume 116, Issue 3, pages 461–462, February 2009
How to Cite
El-Haieg, D., Zidan, A. and El-Nemr, M. (2009), Author response to: The relationship between sonographic fetal thymus size and the components of the systemic fetal inflammatory response syndrome in women with preterm prelabour rupture of membranes. BJOG: An International Journal of Obstetrics & Gynaecology, 116: 461–462. doi: 10.1111/j.1471-0528.2008.02061.x
- Issue published online: 21 JAN 2009
- Article first published online: 21 JAN 2009
- Accepted 28 October 2008.
We agree with Drs Kacerovsky and Boudys1 and with Dr Cho et al.2 that measurement of the thymus transverse diameter is easier than that of the perimeter. At the time we began our study, no normative data were available for the transverse diameter of the fetal thymus. However, in our study, the thymus detection rate was 82.5% in women with prelabour preterm rupture of membranes (PPROM), while it reached 93.5% in uncomplicated pregnancies, which is similar to that of Cho et al.2 (94%). Thymus perimeter was also successfully measured in 99 and 96% of women in Zalel et al.3 and Di Naro et al.4 studies, respectively. In your study, the 100% (19/19) success in measuring the thymus transverse diameter in women with PPROM cannot be only attributed to the easier measurement of the transverse diameter but also it may be due to either a more favourable fetal position or a better maternal body habitus.
Regarding your concern about the probability of the presence of amnionitis in those women who were reported to have no signs of histological inflammation, we would like to confirm that none of them had any signs of inflammation. In our study, histological chorioamnionitis (CA) was defined as the presence of acute inflammatory changes in any of the placental tissue samples (amnion, choriondecidua, and chorionic plate). From the 56 women with PPROM, 30 women had histological CA, of these 13 had also funisitis. This means that 26 (not 13) women had no histological signs of inflammation at all. Small thymus was detected in 73% of those with CA and 92% with funisitis, which is lower than the results you got (although it is not clear in your report whether you had four cases of funisitis or only one). This discrepancy may be attributed to your smaller sample size. However, we believe that fetal thymus size decreases in those cases that developed acute inflammatory response. Since all the studies4–6 conducted in this area included relatively small number of women, further studies conducted on a larger sample size are needed.