my ob doesnt weigh me ever, she says it just makes women obsess that they are too big or too small - and the important things are the health and size of baby and my health so as long as all the scans, blood tests etc are ok she is happy... so pls dont worry about it. If your OB is getting obsessive about the 1kg etc maybe ask for a good explanation as every woman's body is diff and this is an unecessary stress for you to factor in... s/he should be there to reduce your stress not add to it and giving you a 'target' to put on weight may just make you unhealthy.... best of luck!