I just wanted to say, I failed that test too when I was pregnant.
At my appointment they explained it all to me, then gave me blood testing equipment (finger pricking) to take home and I had to record what I was eating, all the while improving it, as well as testing my sugar levels 6 times a day.
I went back in a week later and because my levels were still high, I had to go on insulin. This started at 2units in the morning and 2 at night. It increased the further I got, and when I gave birth i was on 28units morning and night. But once baby was born i no longer had to take the insulin. Then you just have a blood test at 6 weeks after bith to see if it has all settled down. (I never went for mine!)
I had to have an induction at 38 weeks due to GD. However, i was never told this until I was 34 weeks. i should have been told at my second appointment when they put me on insulin, so at 29 weeks.
So all I would say is make sure you ask about this. I wasnt aware it happened, so when I got told, I burst into tears at the hospital, I felt like a right idiot.
Can I just say, i had a natural vaginal delivery, with just Gas and Air for 30mins. I was told i'd need everything going becuase of my size, which wasnt the case. So strive for the delivery you want.
I hope it all goes okay for you.
