Week 6Your baby's jaw, cheeks, chin, eyes, ears, and nose are beginning to form what will eventually become one adorable face. In addition, her kidneys, liver, and lungs are developing, and her heart is now beating 80 times a minute (and getting faster every day).
Week 9Your baby, now the size of a green olive, has grown about an inch since last week. Tiny muscles are beginning to form, so while he might not be ready to pump iron, he's gearing up to move his arms and legs. It's still too soon to feel anything in your belly, but you might be able to hear something at your next checkup.
Week 12By now, your baby weighs a full half-ounce and is about the size of a large plum. Most of his systems are in place, though there's still plenty of maturing to do. For one thing, his fetal digestive system is beginning to practice contraction movements necessary for eating, and his bone marrow is busy making white blood cells.
Week 15She's about the size of an orange this week, her ears have migrated to the sides of her head, and her eyes are moving to the front of her face. Plus, your little smarty-pants can now wiggle her fingers and toes and make breathing movements in preparation for life outside the womb.
Week 18At five and a half inches long and five ounces in weight, he now may be large enough for you to feel him twisting, rolling, kicking, and punching his way around the womb. Plus, he's developing yawning and hiccupping skills.
Week 24Much of that weight comes from accumulating baby fat, as well as from growing organs, bones, and muscle. Those little ears of hers are getting sharper and can hear very loud sounds, from a yapping dog to a jackhammer. Also by now, that fabulous face is almost fully formed, complete with eyelashes, eyebrows, and hair.
Week 28Your little work in progress is now about 2.5 pounds and almost 16 inches long. He's busy adding new skills such as blinking to an already impressive repertoire of tricks like coughing, sucking, hiccuping, and taking practice breaths. Your baby's sleep now includes the REM phase — and that means he could be dreaming already.
Week 32Your belly’s increasing size is a definite clue that your baby is getting bigger every day, weighing in at over three pounds now. Also growing daily is his brain, which is actually starting to look like the real thing with those characteristic grooves and wrinkles. And now that your little genius can regulate his own body temperature and turn up the heat, he'll start shedding lanugo, the downy body hair.
Week 36Your baby, who is now about six pounds and 20 inches long, with soft bones and cartilage to allow a safer journey through the exit door. Most of her systems are ready for prime time, though her digestion system — which has done only practice runs so far — will kick into gear as she takes her first suckle at the breast or bottle.
week 40Congratulations! This week marks the official end of your pregnancy. Your baby probably weighs anywhere from six to nine pounds and measures between 19 and 22 inches (though tons of perfectly healthy babies are smaller or bigger). The bones in his skull haven’t fused yet — Mother Nature’s way of making it easier to get through the birth canal during labor and delivery.