Independent research has never managed to prove that screening for all women for GD is helpful. An Australian collaboration of researchers have recently produced this guideline for the GD test:

http://www.3centres.com.au/guideline..._screening.pdf

The first signs of GD are apparent in urine, anyway, so routine urine screening will pick up women at risk of GD anyway.

And no, I don't think a 9lb baby is a definitive sign of GD... LOL