A unique case of abdominal pregnancy: what are the minimal requirements for placental contact with the maternal vascular bed?

In this report we describe a case of abdominal pregnancy in which the placenta engaged part of the wall of an intra-abdominal membranous sac with only minimal vascular connection with the peritoneal surface. A male infant weighing 3150 gm was delivered at 38 weeks' gestation. We believe this case represents the first report in the literature of an abdominal pregnancy without placental attachment to the maternal viscera.