Reported in this paper are results obtained from morphological investigations of 200 fetal abortions which had occurred in the fourth to sixth months of pregnancy. They were spontaneous abortions and abortions induced primarily for fetal indications (31 cases). Causes are subdivided in this report by placental, fetal, and maternal factors. Fetal causes accounted for 18.5% of all cases (most of them fetal malformations, induced abortions included). Maternal causes accounted for 7.5%, among them edema-proteinuria-hypertension (EPH) gestosis and premature rupture of the amnion. No unambiguous clinical or morphological findings were established as causes in 36 cases, i.e. 18%. The majority of all causes, 55.5% was related to placental factors, among them impaired maturation of the placenta in 14.5%, disorders in maternal circulation in 17%, and inflammatory alterations in 23.5%. Early disorders in placentation accounted for a conspicuously high number of after-birth findings (complex early impairment of placental maturation in 28.6%), and so did maternal circulatory disorders, including retroplacental hemorrhage (55.2%), as well as decidual and membranous inflammations (43.4%).