Hello, Iam 25 years old, aborted my baby with pre eclamsia on 24 weeks....Now iam with 17 weeks 2 days pregnant, my report is Single/multiple pregnancy with Unstable presentation noted, Placenta: Polt, Fotel parameters: BPD mesures: 3:95 CMs, HC mesu: 14.07 cms, FL mesu: 2.62 cms, AC mesu: 10.86 cms, FHR is: 148/min, EF weight is: 193 gm, EDD: 26/7/2014. My BP is 120/90. what does unstable presentation mean?