Alterations in fetal extramedullar hematopoiesis induced by chorioamnitis in second trimester of pregnancy

Purpose: Chorioamnionitis represents a major cause for pregnancy failure in the second trimester. For testing the hypothesis, if there are reactive changes in the fetal liver.

Methods: Clinicopathologic data, 39 abortions, caused by chorioamnionitis, were compared with 32 age-matched controls using H&E- and NASD-staining, and “Berliner Blau“ reaction. Total hematopoiesis, erythropoiesis, myelopoiesis and intracytoplasmatic iron of fetal liver were examined.

Results: In the study group total hematopoiesis was increased (94.9% vs. 84.4%). The same was seen in erythropoiesis (69.2% vs. 56.2%, p>0,05). Chorioamnionitis resulted in a significant increase of fetal myelopoiesis with clustering of leukocytes in 56.4% (p=0.001). Neutrophiles were located predominantly intrasinusoidal and periportal (74.4%), while an isolated periportal location was often observed in controls (50.0%). Isolated perivenous ironstoring was more often seen with chorioamnionitis (28.3% vs. 3.1%) and correlated with the increasing severity of chorioamnionitis.

Conclusions: It can be stated, that infectious diseases like chorioamnionitis increase fetal intrahepatic myelopoiesis as one defense mechanism. The morphology of fetal intrahepatic hematopoiesis and ironstoring might be helpful in the diagnosis of chorioamnionitis.