[Pathoanatomical investigation of early pregnancy loss : Diagnostic possibilities and limitations]

Curettages of early pregnancy losses (EPLs) are frequently sent specimens for pathologic anatomic investigation, because about 15% of the clinically diagnosed pregnancies result in a miscarriage. According to recently published German recommendations, every early miscarriage should be investigated morphologically. In a careful macroscopic preparation, the different compartments (decidua, villous tissue, and possibly embryo/fetus) should be identified and submitted for histologic diagnosis. The most important issues for the microscopic investigation are documentation of an intrauterine pregnancy (to rule out extrauterine gravidity), screening for gestational trophoblastic disease, and-if possible-detection of pathologic anatomic visible causal factors for early pregnancy loss. In some instances, especially in the case of repeated spontaneous miscarriage in the first trimester, the supplement of conventional cytogenetic analysis and molecular genetic and molecular pathologic methods may be useful for confirmation of a diagnosis. A standardized procedure for asservation of native trophoblastic tissue should be established in the department. The detection of early complete hydatidiform mole and partial hydatidiform mole is important, since these lesions have a risk for the subsequent development of persisting gestational trophoblastic disease. Histologic characters of sporadic chromosomal aberrations (the most frequent etiology of EPLs) in miscarriage specimens are abnormalities of the villous tissue (trophoblast, stroma, and vessels).Chronic histiocytic intervillositis (CHI), massive perivillous fibrin deposition (MFD), and chronic deciduitis are morphologically defined lesions with partly high recurrence risk. These placental diseases can be causal factors for clinical habitual miscarriage.Although the limitations of the morphologic diagnostic procedure have to be recognized, the standardized pathologic anatomic investigation of miscarriage specimens can render information on the etiology and recurrence risk in some cases of early pregnancy loss.