<s>[INST] My grandchildren a boy & girl are twins born oct 23 2012 The girl who is a bit smaller experiences a lot of twitching all over her body especially when she id sleeping. Is this normal? Their birth weights were 4.12 and 4.6 lbs at birth their wieght currently is 5.11 and 5.7 lbs [/INST] Dear friend, I am telling you if a baby is born with low both weight he or she needs a little more time to cope with physiological adversity in the outer world. So in your granddaughters case she is physiologically weak. There can be various reason behind twitching of a small child, like glucose level fall in blood .so you need to take her to a child specialist for a check-up of her blood and developmental profile. If the report comes to you as normal as you don't need to worry much about her health. Thank you. </s>