Placentology evolving rapidly to our understanding of the molecular, cellular and epigenetic mechanisms which underlying normal placental development and placental pathophysiology is rapidly increasing and the making opportunities in prediction, prevention and treatment of this condition are expanding likewise. It is the only relatively recently that attention which has been directed to studies of the uterine side of the placenta to look for possible defects that might explain otherwise unexplainable pregnancy complications .Preeclampsia and intrauterine fetal growth retardation are the two such disorders in which a new information has come to light by study of placental bed biopsies and occasional caesarean hysterectomy specimens. It will be less easy to apply these techniques to such problems as spontaneous abortion and antepartum haemorrhage, but reemphasizing what should be the self-evident importance of the establishment and development of the uteroplacental blood supply might help reorient thinking about these and other important complications of pregnancy. Fresh thoughts are required too about etiology and history of ectopic pregnancy, not so much as its own sake but more because of what it tells us about the nidation and placentation in general. It is now become difficult to insist on stringent criteria for endometrium in human gestation, with all that this implies for the woman under investigation for infertility.