The Role of Morphology in Combination with Ploidy Analysis in Characterizing Early Gestational Abortion

Morphology in combination with flow cytometry is an inexpensive and fast tool to characterize important reasons for early gestational loss. Early partial hydatidiform moles are especially difficult to identify as not all have developed the typical histological features of central cistern formation and trophoblastic hyperplasia of the chorionic villi. Angiomatoid formation of the blood vessels, irregular chorionic villi, diffuse villous stromal fibrosis, trophoblastic pseudoinclusions, and pleomorphic trophoblast at the implantation site have therefore been proposed as additional morphological criteria. In our study, we investigated the correlation between morphological features and results of ploidy analysis to assess the additional criteria for practical use. Morphological features of the placentas of up to 13 weeks of gestation were evaluated on hematoxylin and eosin sections. Ploidy analysis was performed by flow cytometry on formalin-fixed, paraffin-embedded tissue. Statistical analysis was performed by binary logistic regression. One hundred fifty samples were included in the study. Of the samples, 23 were triploid, 19 were tetraploid, and the remaining ones were diploid. Statistical analysis showed a poor predictive power based on all morphological criteria alone. The most important result of this study was the identification of five triploid placentas that showed diffuse fibrosis of the chorionic villi, angiomatoid changes of the blood vessels, trophoblastic pseudoinclusions, and focal pleomorphic changes at the implantation site, but none of the classical morphological features of triploid pregnancies were identified. Our study demonstrates that the use of additional morphological criteria increases the number of missed abortions with identified causes for pregnancy loss.