At 16 weeks:

- Muscle tissue and bone continue to form, creating a more complete skeleton.

- Skin begins to form. You can nearly see through it.

- Meconium (mih-KOH-nee-uhm) develops in your baby's intestinal tract. This will be your baby's first bowel movement.

- Your baby makes sucking motions with the mouth (sucking reflex).

- Your baby reaches a length of about 4 to 5 inches and weighs almost 3 ounces.

At 20 weeks:

- Your baby is more active. You might feel slight fluttering.

- Your baby is covered by fine, downy hair called lanugo (luh-NOO-goh) and a waxy coating called vernix. This protects the forming skin underneath.

- Eyebrows, eyelashes, fingernails, and toenails have formed. Your baby can even scratch itself.

- Your baby can hear and swallow.

- Now halfway through your pregnancy, your baby is about 6 inches long and weighs about 9 ounces.

At 24 weeks:

- Bone marrow begins to make blood cells.

- Taste buds form on your baby's tongue.

- Footprints and fingerprints have formed.

- Real hair begins to grow on your baby's head.

- The lungs are formed, but do not work.

- The hand and startle reflex develop.

- Your baby sleeps and wakes regularly.

- If your baby is a boy, his testicles begin to move from the abdomen into the scrotum. If your baby is a girl, her uterus and ovaries are in place, and a lifetime supply of eggs have formed in the ovaries.

- Your baby stores fat and has gained quite a bit of weight. Now at about 12 inches long, your baby weighs about 1½ pounds.

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