The objective of our work was to study the effect of parity the parity of the does, the intra uterine position and vascularization of the fetuses and their number per horn on, available uterine space and placentae development in the rabbit at two stages (nulliparous and primiparous). To this aim, twenty rabbit does of locally Algerian population were distributed in two groups of 10 each (nulliparous and primiparous). The does were mated and slaughtered on 24 th day of gestation. In the group of fetuses receiving poor blood supply (? 4 blood vessels), the individual weight and the crown-rump were lower (- 24.4 and - 12.6% respectively; p