Congratulations, it is very magical isn't it. My first was also like that during his scan - he also slept all the way through 36 hours of labour and a c-section! He slept through the night in hospital and apart from an odd few occasions when he hasn't been well, he has slept ever since. He is now 7 and still sleeps for 11 hours every night - he is now 4 foot 3, so his sleep is obviously doing him some good. He is a very chilled calm boy, so hopefully it is a good omen! lol