This study retrospectively evaluated the histopathological criteria commonly used in the literature on the diagnosis of hydatidiform mole, in correlation with the diagnosis rendered previously. The molar and non-molar cases seen in the first-trimester of pregnancy were separately reviewed by two pathologists. The correlation between the consensual histological diagnosis and the ploidy status was then evaluated. We retrospectively studied 89 specimens of abortus conception, including 35 complete hydatidiform moles (CHM), 12 partial hydatidiform moles (PHM), and 42 hydropic abortions (HA). The final histopathological diagnosis was compared with the results of DNA content detected by imaging analyzer (Samba 200), studying all cases of molar pregnancy and 4 cases of HA (initially diagnosed as molar pregnancies). In the consensus histological diagnosis, the cases were reclassified as follows: 30 CHM (initial diagnosis (ID): 27 CHM and 3 PHM), 12 PHM (ID: 6 PHM and 6 CHM), and one case with a persistent problem in differentiating PHM from HA and 46 HA (ID: 42 HA, 2 CHM, and 2 PHM). An agreement between the two pathologists was reached in 77 cases (K=0.72, 0.52, and 0.9, respectively, for CHM, PHM, and HA). The ploidy study demonstrated diploidy in 56.6% (17/30) of CHM and triploidy in 58.3% (7/12) of PHM. In the 4 cases of HA studied, 3 were diploid and 1 case was aneuploid. Our study demonstrated that several histopathological criteria could be used for the distinction between PHM, CHM, and HA. However, the study of DNA cannot be the technique of choice to distinguish between these entities. Some cases remain problematic since the morphological criteria are not easily reproducible. New sensitive techniques might resolve these dilemmas.