3 cm Small

My mother had a doctor's appointment yesterday and I am still measuring 3 cm small. In case someone doesn't know - each doctor visit the doctor measures the length of the pregnant belly. The number of centimeters the belly should measure should equal the number of weeks pregnant. Since I was about 20 weeks along, I have been consistantly measuring 2 to 3 cm smaller than I should. The doctor never was worried about it, but now that we are approaching the scheduled c/s (28 days away!!) the doctor is showing some signs of concern. So next Wednesday they have scheduled a sonogram to look at me. There's nothing to worry about as far as I know, but I'll post an update after we know a little more. Especially if it means the date of my arrival to be changed...