The measurements are generally plus or minus 2 cm as far as comparing cm to weeks pregnant (so, if you are 29 weeks a typical range is 27-31 cm). But there is also a 0.5 cm margin of error for measurements with a tape measure. Which is why it is always good to measure twice, cut once when doing carpentry.
So, I'd say not to worry if they aren't worried. But to also trust your gut: if you are concerned, let your provider know.
Last edited by valerievalira; 07-21-2014 at 07:27 PM.