The embryo's cells will develop into organs and body parts. Also developing this week are the fluid‑filled amnion, which protects baby, and the yolk sac, which provides nourishment early on.

Week 6 Your baby's heart is beating! Small buds that will become the arms and legs are appearing. Also forming this week are the digestive and respiratory systems.

Week 7 Your baby's facial features are taking shape this week. The mouth, nose, ears, and eyes will become more defined. Baby's tiny arm bud now has a hand on the end of it, which looks like a paddle.


Week 8 Toe buds and finger buds take shape this week.

Week 12 Tiny fingernails and toenails start to form this week, which is the end of the first trimester.

Week 13 This week marks the beginning of the second trimester. Even though you might not feel it yet, baby is moving and kicking often. In fact, your baby may be able to put a thumb in the mouth.

Week 15 This week, your baby's eyebrows are growing and hair starts to appear on your baby's head.

Week 16 Some fine hairs, called lanugo, have developed on your baby's face. This soft, colorless hair protects the skin and will eventually cover most of your baby's body until it is shed before delivery.
 
Week 17 Your baby is still very tiny, about 5 inches in length and weighing about 5 ounces. Your baby is able to swallow amniotic fluid, and may get hiccups as a result!

Week 19 A waxy, cheese‑like substance called vernix is covering your baby to help protect delicate skin from being chapped or scratched.

Week 20 You're now halfway through your pregnancy. If you haven't already, you might begin to feel baby's first kicks.

Week 21 Baby's ears have moved into their final position on the side of the head. Your baby is probably starting to hear sounds!

Week 22 Taste buds are forming and your baby's sense of touch is developing. Your baby may be able to taste the amniotic fluid or touch the toes!

Week 24 This week, your baby will be practicing breathing movements as the lungs develop. He or she still relies on the placenta for oxygen.

Week 25 Your baby's hearing continues to develop. Baby might be able to hear your voice, music, and the voices of others close by.

Week 26 This is the last week of the second trimester. Your little one will gain much of that kissable "baby fat" over the third trimester.

Week 27 This is the first week of the third trimester. Baby's lungs, liver, and immune system still need to fully mature, but if born now, your baby would have a very good chance of survival.

Week 29 Your baby is starting to gain weight at a quicker pace. What used to be flutters of movement now may be hard jabs and kicks that take your breath away.

Week 30 Your baby continues to make breathing movements, getting ready to take his or her first breaths at birth. If you feel regular twitches in your uterus from time to time, it could be hiccups!

Week 31 Your baby pees several cups of urine a day into the amniotic fluid. This fluid helps keep your womb cushiony so that your baby is protected.

Your baby is probably in position for delivery. Your health care provider can tell you if baby is positioned head‑ or bottom‑first.

Week 37 Baby's eyesight is so developed now that if a bright light shines on your belly, your baby may see it and turn toward it.

Week 38 Baby has likely "dropped" into the pelvis in preparation for birth. This means that your bladder is squished, making you have to pee more often.

Week 39 Your baby is considered full‑term this week. At birth, don't be alarmed if your baby isn't picture‑perfect. Newborns may have a temporarily misshapen head from the birth canal, rashes, and more.

Week 40 Babies born around this time weigh about 7 pounds, 4 ounces and measure about 20 inches from head to toe. Boys tend to be bigger than girls. Enjoy your masterpiece!