[Cinematographic and morphometric analysis of in vitro behavior of blastocysts of the mouse].

The behaviour of the mouse blastocyst in vitro was studied by time-lapse cinematography and analysed by morphometry. Three types of behaviour were observed: discontinuous expansion interrupted by rapid contractions and followed or not by hatching; practically continuous expansion followed by hatching. This demonstrates that the pulsatile activity of the blastocyst is not a necessary condition of hatching. Analysis of the rate and delay of hatching in vitro as compared to the conditions in utero is in favour of the existence of a uterine factor insuring partial lysis of the zona pellucida and helping the mechanical action of the blastocyst. Hatching by herniation through a reduced opening of the zona was occasionally observed. The process of in vitro implantation could be followed by cinematography.