Hi i am 20wks pregnant and at my first ultrasound it has been found that one baby is quite smaller than the other. twin a is a boy who is 100gm bigger than twin b who is a girl. my dr has said that chances are that my little girl may not make it 'statistically'. she has all her parts and a good heart beat and i hav to hav regular check ups to see how she is growing. has anyone else gone through this, is it common and does the smaller one always stay small or does it catch up or is it not good. i am really concerned and shattered at this news?