Aims: Chorioangiomas are rare hamartomatous lesions. Possible correlations between their occurrence and the progression of a pregnancy have been objects of discussions for quite some time.
Methods: In a retrospective study 22439 unselected placentas were examined for incidences of chorioangiomas, morphological features and accompanying clinical characteristics.
Results: Chorioangiomas occur in 0.61% of pregnancies, they are mainly microscopically small, and 55% of them are localized subchorial. The rate of their occurrence rises almost linearly with maternal age; chorioangiomas are found most often in women who are over 30 years old. Hypertension and diabetes are found more often in combination with chorioangiomas than they are in otherwise normal pregnancies. In 72% of all cases girls were born; in 33% we also observed malfunctions in the maturation processes of the placental parenchyma, in particular arrested and delayed maturation of the villi. Premature births occur approximately three times more often in chorioangioma pregnancies than in normal ones. Chorioangiomas are often found in primipara and twin pregnancies.