The basal laminas and fixed on them anchoring villi after late abortion on 18-28 weeks of pregnancy have been studied. The pregnancies were without complication and abortions were activated by "Enzaprost" injection. 4 types of anchoring villi were studied: without cytotrophoblastic invasion, with maximal, medium and minimal density of cytotrophoblastic distribution and depth of its invasion into endometrium from villi's base. The maximum of its migration activity was in 18-20 and 22-23 weeks of pregnancy. The activity decay of cytotrophoblastic invasion was been found in the end of the second trimester Anatomic contact of villi's base with endometrium increased by them parallel attachment or horseshoe-shaped form. The estimation of villi's quantity and density of cytotrophoblastic distribution in their base can use for definition of cytotrophoblastic invasion rate in the adjacent myometrium of pregnant women on the second trimester.