I had an ultrasound at 32 wks which estimated that at 32wks, bubs was weighing approx 3kgs (6lbs 6oz) ... so if he/she keeps growing at the same rate, who knows what the estimated birth weight would be!!!

Having said that, I have read research which compared estimated weights gained via (1) ultrasound, (2) fundal height and (3) an experienced obstetrician 'guessing' using touch. The most accurate turned out to be the experienced OB ... so I am determined not to worry at all about my u/s guesstimate ... I'll know how much my baby weighs after they're born