Placental findings in spontaneous abortions and stillbirths.

Placentae and membranes of 360 spontaneous abortions and stillbirths were studied by light microscopy and compared to 100 induced abortions of 2-5 months gestation. The placental findings were correlated with morphological and chromosomal studies of the fetuses. A high incidence of hydatid degeneration was found in early spontaneous abortions (less than 12 weeks of age), especially in "blighted ova.