GU is 100% safe according to my dr. I use the no caffeine GU's. She told me to bring them to the hospital with me because they will fuel you through delivery! A new market for GU? maybe!?!!
I used the GU gummy chew things on my half, I was 4 weeks pregnant. They worked great, basically popped one before every water station and as a ran by took two waters since its just as important not to get dehydrated.
Re: 1/2 marathon at just almost 1 month- which fuels are safe?
I went with the jelly belly sport beans when I did my half while pregnant. But I don't like the Gu in general because it's too sticky for my teeth!
I ended up drinking a LOT more water than I was expecting to, so plan accordingly!