I need to be tested for gestational diabetes at 28 weeks, but that's because my mother is a type 1 diabetic. They think it could have contributed to the weight loss.
I honestly wouldn't worry, at this stage baby weighs hardly anything, 2kg seems like an ok weight gain to me. I didn't start really gaining weight until I was 30 weeks with my first x
I lost a stone when I was hospitalised 🤦♀️ but managed to put that back on when baby was out due to not eating properly when he was in hospital.
They never questioned my weight gain or losses on either pregnancies