I'm sorry to hear they're now worried about baby being big because of GD
I declined the test because I've had it done before for a couple reasons, none of which being risks to the drink itself. The biggest ones being that I think the *label* of gestational diabetes is worse than having it most of the time. Since most people who get diagnosed with it find that their sugars are still within normal ranges when they test at home eating their normal diet, but now having the diagnosis means being pushed into early inductions that are totally unnecessary in their case. And that's the main thing I wanted to avoid. But also, like you, when you have kids already it's *so* inconvenient to sit around for 3 hours waiting for the rest to be finished. And I don't believe it's healthy or good to deprive pregnant women of food for that many hours . I am not a pleasant person when I am hungry, especially when I'm pregnant lol. Since I homeschool I can't even go in after school drop off.
Anyway I chose to test my blood sugars regularly at home instead, because GD diagnosis or not, that's the important part to actually be aware of - if blood sugar levels are out of range and if so, for how long. Gestational diabetes with normal blood sugar levels don't carry the risks of gestational diabetes, as it's *uncontrolled* sugars that cause excessive growth in babies, and can cause them to have blood sugar issues after birth.
So long story short, by testing at home 4x a day I've been able to see what my blood sugar is doing and take appropriate actions (avoiding eating trigger foods that do cause a blood sugar spike - which with GD are very unpredictable. I've discovered I can eat most things that are a no no for diabetics just fine, but that there are other foods that I wouldn't expect to cause a spike that do, which are easy enough avoided)
If my sugars were out of range and not able to be controlled with diet then I would have at that point been fine with having the diagnosis on my file because I would need the medications and extra monitoring that comes with GD. Luckily I have midwives who agree with my perspective and it's been a non-issue.
A glucose monitor can be picked up quite inexpensively from the pharmacy without a prescription - it's the strips that are crazy expensive though. Testing your fasting blood sugar and then either 1 or 2 hours after meals (it doesn't matter when as long as you record it since there are different ranges you're looking for at each time) for 4 days will give a good indication of whether your baby is big due to gestational diabetes or not, since it's the uncontrolled GD that causes that.
If your numbers come back high, then absolutely go through with the inconvenience of the test so you can get help getting them under control. But if all your numbers come back within range (and you didn't change your diet), then it's very unlikely that your baby is big as a result of GD