Your baby weighs about 70 grams....he is about 9.1 cm from head to bottom of the hips....your little guest hiccups frequently and is learning to do this before he breathes....because his trachea is filled with fluid instead of air, he can't make any sound....now his legs are growing more than his hands and all his organs are better...until diagnosed..ultrasound which is about 18-20 It's a week pregnant.... Legs: His legs are longer than his hands and he can move all his limbs.... Water sac and its fluid: Your baby swallows the fluid inside the water sac with his tail and returns it with his tail, helping the development of the air sacs inside his lungs... Hold your belly, he may move towards it and away from it....