You've made it through your first trimester, and it's likely that the morning sickness and excessive tiredness are starting to subside. As some of your symptoms start to diminish, your burgeoning belly is a sign that your baby's growing. During the beginning of the second trimester -- weeks 14 through 17 -- your baby is developing everything from fingerprints to sweat glands.
Height and Weight
Judging by the relatively small size of your belly, you know that your baby is far from full-term size. During the first trimester, your baby spent much of its time developing basic body structures and organs. The beginning of the second trimester kicks off a time of overall growth. Even though your bump may be expanding, during weeks 14 through 17 your baby is typically around 4.5 to 5 inches long and weighs 4 ounces.
As the second trimester begins, you may begin to feel your baby moving. The little flutter in your tummy is your baby moving from side to side, kicking or turning around. If you aren't feeling movement yet, don't worry. Many women, especially first-time moms, do not feel movement until 18 or 19 weeks. The baby is also moving its mouth now, making sucking motions. Even though your baby can make these movements, they aren't purposeful motions. At this stage of development, most fetal movements are reflexive.
Skin and Hair
While your 14- to 17-week old fetus doesn't have the angelic soft skin or fluffy frame of hair that a newborn has, your baby is developing these body parts during the second trimester. Both your baby's skin and hair are almost transparent, making the fetus appear see-through. The hair, called lanugo at this point, is fine and covers most of the body. The lanugo will start to fall out during your third trimester, but some may stick around until after birth.
By week 17, your baby has fully developed fingers with their unique fingerprints in place. During the first part of the second trimester, your baby's fingers and toes are separating from each other to look like yours do. Likewise, your baby is already growing fingernails and toenails.