Right now, my wife is having a 7 month pregnancy. :D Everytime we see our baby through USG when we visit our doctor, our baby looks very calm. He only made a simple movement such as chewing. Will my boy be a calm/introvert boy?
This is entirely based on my experience so your mileage may vary, and it's not at all scientific. I felt I knew some aspects of my child's personality while she was still in my womb. I knew she would be strong and stubborn because of the way she kicked. I love my baby to the hilt but she's been stubborn since the day she was born.
That said, babies in the womb spend a lot of time sleeping. Chances are, your baby is sleeping during an ultrasound. They recommended I drink orange juice 1 hr - 1/2 hr before the ultrasound, figuring that the natural sugar would wake her up. It didn't work once (she slept the whole time and had her body turned so we couldn't see her face) but worked well the second time, although the second u/s she was asleep for some of it.
I'd ask your wife what her sense of the baby is, but not put too much stock in what the ultrasound shows to guess how extroverted or active the baby will be.
Here is research that I found on this topic at http://www.ncbi.nlm.nih.gov/pubmed/12115294.
It appears that the relationship between fetal movement and neonatal behavior is inconsistent. Fetal activity did appear to predict temperament related to self regulatory behaviors in early childhood. Small positive associations were detected between motor behavior at 36 weeks gestation and neonatal irritability and motor development.
So, no it does not appear that fetal activity is a good predictor of personality even though there may be some statistical association.
My son was very, very active during ultrasounds. It wasn't until roughly 7 months that we could even get a look at his face because he kept moving around so much.
However, despite his rowdy pre-birth behavior, he's generally very calm and even-tempered.
Activity on ultrasound is not really an indication of personality, in my (admittedly limited) experience. As Corvus Melori pointed out, babies spend a lot of time sleeping before they are born, and you may have just been unlucky in the timing of your ultrasounds. The juice trick she mentioned is an excellent idea, and may result in your baby being considerably more active.
This may be true, but may work in the other that way you expect. If you decide your child seems calm/active/stubborn while watching her/him in the womb it may affect the way you treat the child and what character features she/he develops.
I think giving labels to the unborn child or any child at all is not proper thing to do. I think there's related situation described in one of this books (or a supplement to it):
The woman heard her child is stubborn during giving birth and one day she noticed it somehow affected the way she thought of him ever since.
I think it's hard to give a conclusive answer.
My mother told me when my she was carrying me, that she could feel that I would be a calm boy, unlike by brother. Indeed I was and still am much calmer than my brother. This was something my mother could feel by carrying me around in her womb.
I doubt that a few USG sessions will give you the same idea. Maybe you should instead ask your wife how she perceives your boy. She is the one carrying him around after all.