Your baby’s skin has become opaque (it had been see-through),
but it is still immature. The retina of the eye continues to
form, but that also is not mature yet. The circulation to the
lungs is forming, and the lungs are beginning to develop
surfactant (a substance that keeps the lungs from sticking to
themselves), however the lungs will be one of the last parts of
your baby to fully mature. His body has caught up with his head,
and although the head is still large compared to an adult, your
baby’s body and head are in the right proportions for a newborn.
His brainwaves also resemble those of a full-term newborn. He is
developing a sleep-wake pattern and may be developing an active
time that is pretty regular from day to day. At the end of the
24th week your baby will be around 10 inches from crown to rump
and weigh 2 pounds. For most women the second trimester has
brought some welcome changes. The uterus is too large for the
pelvis, so there is less pressure on the bladder, but the uterus
is not quite large