38 st week of pregnancy: a difficult weight estimation

Your baby may weigh 3.5 kg and measure 50 cm. But this is only an average. There are small babies weighing 2.5 kg and large babies weighing over 4 kg. The estimate of the fetal weight at this term cannot be too precise and may vary by more or less 10%. 

Its head circumference, averaging 9.5 cm, is the largest part of its body. The fontanelles, the membranous space between the bones of the skull of newborns, can be shaped as they pass through the pelvis and gradually ossify as they grow. The brain weighs between 300 and 350 grams and will continue to mature for many years after birth.