31 weeks - did you know?

• Baby Boy is about 16.5 inches long and weighs anywhere from 3.5 to 4 pounds. 
• He is continuing to develop a layer of fat under his skin.  This is in preparation for his arrival into the world and gives him more of a newborn appearance.  During the next several weeks he will really begin to put on the weight, about a ½ lb per week from now until about two weeks before birth.  Average size newborn is about 7.5 lbs and 19 to 21 inches long.
• This week marks an incredible milestone in his lung development.  Before now, the air sacs and branches in his lungs were present but not functionable. The lungs were not able to inflate properly. However, now there is surfactant being produced in his lungs. Surfactant prevents the his lungs from collapsing outside of the uterus and he is able to take in air and breathe properly.
• His ear is almost completely developed both inside and out. He can hear your voice and other familiar sounds that he will recognize after birth.
• Baby boy's fingernails have grown to the end of his fingers and he may scratch himself while in the womb.
• Baby boy's iris color begins to appear around the thirty-first week. Most babies are born with dark blueish-brown or bluish-gray eyes, but this shade almost always changes after birth. True eye color won't be apparent for six to nine months -- final formation of eye pigmentation happens in response to exposure to the strong light of the outside world.  In the meantime, his eyes are being readied for life after birth. Pupils begin to dilate in response to the soft, pinkish-red light that filters into the uterus. Eyes are usually open during alert times and closed during sleep.