16 to 20 Weeks

Fetal baby later in second trimester

Week 16:

The baby is now about 4-5 inches long – the size of an avocado. Her heart is pumping about 25 quarts of blood each day and her body is covered with a layer of downy hair called lanugo. Fingernails and toenails are forming now. Preborn baby now has coordinated movements; is able to roll over in amniotic fluid.

Week 20:

At this age, the baby’s eyelashes can be seen and the lungs are developing. The baby is about 12 inches long and weighs 1/2 to 1 pound. The mother definitely has begun to feel movement… baby is large enough to lean on one side of the womb and push on the other which can now be felt by mother.

A creamy, white substance called vernix protects the baby from his long immersion in amniotic fluid. He’s swallowing more and giving his digestive system a workout. During an ultrasound, you might see him sucking his thumb.

Baby has completed all of these stages of development within one half of the time in the womb before birth. Just another 20 weeks to go…