[Mechanism of placental detachment in the postnatal period]

Separation of the placenta was examined by the echoscopic and tocographic methods in 62 women who gave birth to healthy full-term babies. The placentas separated spontaneously, in 61 women. The amplitude time characteristics of the after-birth period are presented, and the echoscopic picture of separation of the placenta is described. The findings evidence the presence of symmetrical and asymmetrical contractions of the uterine walls, governed by the placental position in the uterus, and the growing tension of the placenta during labor because of its compression with uterine walls.