Ohh I was about to post a similar thread. At 20 weeks I had put on 10kg also. Im now 24+2 and have put on 15kg all up so thats 5 kg in 4 weeks. Im starting to really stress about it as my local hospital has a BMI cut off and if I go over that Im labelled high risk and cant birth there. I have worked out I have 20kg to go until I reach that point so I really hope the weight gain slows down soon.