Unstable lie This is a condition where the presentation of the fetus is constantly changed beyond 36th week of pregnancy when it should have been stabiliseed The causes are those which prevent the presenting pa to remain fixed in the lower pole of the uterus that is grand multipara,hhydramnios,contracted pelvis,placenta prae,pelvic tumor At admission the investigation is directed to exclude placenta prae,contracted pelvis,or congenital malformation of the fetus with the help of sonography for the localisation of placenta D.C.DUTTA&;S TEXTBOOK OF OBSTETRICS,Pg no:397,7th edition