A placenta in which there are areas of thinning, sometimes extending to entire absence of placental tissue. ... (05 Mar 2000) ... 
(plә-sen´tә fen″ә-stra´tә) one that has spots where placental tissue is lacking.
Type: Term Definitions: 1. a placenta in which there are areas of thinning, sometimes extending to entire absence of placental tissue.