Hi, my 17 year old daughter is 25 weeks pregnant and as yet has not gained any weight she still only weighs 8 stone the midwife does not seem worried by this. I am though. Also she has been having night cramps the dr says this is due to lack of calcium.. I have spoken to her but she is still a teenager and her diet is ok but not great. she does eat lots of cheese and dairy products. is this ok do you think?