You’re not really pregnant yet; the clock starts ticking from the first day of your last period. So even though pregnancies are said to be 40 weeks long, you actually carry your baby for only 38 weeks or so. View all Week 1 »
The gastrointestinal tract, spinal cord, heart, brain, blood and blood vessels begin to form. The embryo is 1∕16 to 1∕8 inch long “crown to rump” (the measurement that’s used until week 13). View all Week 5 »
The heart begins to pump blood, and the neural tube that will become the spine closes (which is why taking folic acid early is essential).The embryo takes on a C-shape; arm and leg buds begin to form; and the skin is translucent. Length: about 1∕4 inch. Fetus fact: The heart will beat 54 million times before birth! View all Week 6 »
The head is about 1∕3 the size of the entire embryo. The brain and face are developing rapidly, and nostrils and lenses of the eyes begin to form. Arm buds become paddle-shaped; hands begin to form. Length: about 1∕3 inch. View all Week 7 »
Brainwave activity starts. Fingers and toes begin to form and are webbed. Lungs, ears, eyes, upper lip and nose start to form. The body is beginning to straighten, and subtle movements begin. Length: about 1∕2 inch. View all Week 8 »
The heart is almost completely developed. Eyelids are forming, as are hair follicles and nipples; the embryo can hiccup now. Fingers and toes are no longer webbed. The arms develop bones, and the hands begin to touch the face. The legs start to move. Length: about 3∕4 inch. View all Week 9 »
The developing baby is now called a fetus. The eyelids begin to fuse to protect the eyes. The fetus begins doing occasional breathing movements, although it gets oxygen through the umbilical cord. The skin becomes less translucent, and genitals begin to form. Length: almost 1 ¼ inches. View all Week 10 »
Nearly all the organs and body structures are formed and beginning to function. Genitals begin to take on either male or female form. The head makes up about half of the fetus’s body. Length: about 2 inches. Fetus fact: The fetus can sigh, stretch, move its head and suck its thumb. View all Week 11 »
The nose, lips and taste buds are formed. The head is covered by a fine, soft hair called lanugo. Length: about 5 inches; weight: about 2 ounces. Fetus fact: Starting now, female fetuses show mouth movements much more often than males. View all Week 14 »
Your baby is about 4 to 4 1/2 inches and about 1 3/4 of an ounce. If you could see your baby's face, you might be able to see her wince and grimace, because her facial muscles are developing and flexing. All of her tiny organs, nerves, and muscles are starting to function. The intestines have moved farther into the baby's body; her liver begins to secrete bile, which will later aid in the digestion of fats; and her pancreas begins to produce insulin, a hormone which turns sugar into energy. View all Week 15 »
Your baby weighs about 2.8 ounces (79 grams) and is about 4 1/2 inches from crown to rump—roughly the size of a small gerbil. At any time, you will begin to feel fetal movement as your baby's bones harden, and she starts a big growth spurt. Your baby has plenty of room: At this point, she could fit in the palm of your hand. This is a great time to be a fetus. View all Week 16 »
Your baby is about as wide as your palm, about six inches tall, and weighs about four ounces—about as much as a bar of soap. She now weighs more than your placenta. Your baby is now covered with a downy layer of lanugo, which swirls in fingerprint-like formation over her whole body. Her skin is still thin. Brown fat, a special type of fat that plays a role in body heat generation, is being deposited. View all Week 17 »
Fat is being deposited throughout the body. Teeth have started to form. The fetus begins to hear sounds in your body (such as your heart beating) and may even startle at loud noises. Length: about 8 inches; weight: 6 ounces View all Week 18 »
Your baby weighs about 8 1/2 ounces, and measures about 6 inches long.If the baby is a girl, early ovaries contain follicles with forming eggs. Soon, half of the genetic material for your potential future grandchildren will be formed. Pictures of babies at this age show them touching the membrane of the amniotic sac, touching their own faces, reaching for the umbilical cord, pedaling their legs, and sucking their thumbs. View all Week 19 »
A white, creamy substance called vernix caseosa protects the skin from its aqueous environment. Sweat glands form. Length: about 10 inches; weight: 9 ounces. Fetus fact: Starting now, immunities are being transferred from you to the fetus. View all Week 20 »
The testicles begin to descend into the groin from the abdomen; the uterus and ovaries have developed. Body proportions are similar to a newborn’s, though the fetus is still thin. The eyes are formed but lack pigmentation. Length: about 11 1∕2 inches; weight: about 1 pound. View all Week 23 »
The fetus develops waking/sleeping patterns. Real hair (not lanugo) begins to grow on the head. Length: about 12 inches; weight: 1 ¼ pounds. Fetus fact: If born now, your baby would have about a 50 percent chance of surviving. View all Week 24 »
The eyelids separate and the eyes are starting to open. Lungs are beginning to develop surfactant, which allows them to inflate. The fetus begins to sleep for longer periods, often when you do. Length: 14 inches; weight: almost 2 pounds. View all Week 26 »
The fetus can taste and smell, and the eyes can produce tears. The bones are almost fully developed though still soft. Weight gain is rapid from now on. Length: about 15 inches; weight: more than 2 1∕2 pounds. Fetus fact: The brain will increase 400 percent to 500 percent in weight between now and delivery. View all Week 28 »
Your baby is about two and a half pounds and would be between fifteen and seventeen inches tall if she could stand.Your baby's adrenal glands are producing a chemical which will be made into estriol (a form of estrogen) by the placenta. This estriol is thought to stimulate the production of prolactin by your body, and the prolactin makes you produce milk. So even if your baby comes early, you'll still be able to breastfeed. View all Week 29 »
Your baby weighs between 2 1/2 and 3 1/2 pounds. She continues to gain weight at a faster pace than she lengthens, which will give her those cute chubby cheeks. She's about fourteen to sixteen inches tall, although individual growth rates vary. View all Week 31 »
The fetus practices breathing motions in preparation for birth. All five senses are developed, and REM (dream-cycle) sleep is beginning. Lanugo begins to disappear. Length: about 17 inches; weight: about 4 pounds. Fetus fact: If your baby were born now, he would have an excellent chance of surviving without life-threatening complications. View all Week 32 »
The fetus is taking deep breaths. The eyes can blink and are open when it’s awake and closed when asleep, and the pupils dilate and constrict in reaction to light. Length: about 18 inches; weight: about 5 pounds. View all Week 34 »
At more than five pounds and between sixteen and twenty inches, your baby is becoming more ready for birth with every passing hour. She's the size of a small roasting chicken.Her nervous system and immune system are still maturing, and she's adding the fat that she'll need to regulate her body temperature. But, everything else, from her toenails to the hair on her head, is fully formed. If she were born now, she'd have more than a ninety-nine percent chance of surviving. View all Week 35 »
Your baby is now 20-21 inches or so and weighs about 6-7 pounds; he looks very much like a newborn. In the vast majority of pregnancies, the fetus begins to move into delivery position. View all Week 37 »
The average newborn has a length of 21 1/2 inches and weighs 7 1/2 pounds. She is fully developed, though still adding connections between neurons in the brain (this continues well after birth). Her nails have been growing and now reach to the ends of her fingers and toes. Her movements are quite restricted by her close quarters. View all Week 38 »
You're in the home stretch! After nine months of growth and development, your baby is ready to be born, or nearly so. At week 39, your baby is fully developed and anywhere from 17-23 inches long and weighs 6-10 pounds. Don't be frightened if your OB-GYN says your baby is large: It's extremely difficult to judge a baby's weight accurately from the outside. View all Week 39 »
What you need to do before baby, broken down by trimesters and weeks.
Week 29 Start shopping for items you'll need in the hospital (nursing bras, nightgown, baby clothes, car seat) and at home (diapers, wipes, etc.).
Week 30 Attend childbirth classes. The sessions should end by week 36. You'll also want to call your health insurance company and alert them to your due date. Find out any requirements they may have about adding a baby to your policy.
Week 31 Interview doulas or labor coaches—they book up quickly.
Week 32 Have your baby shower about two months before your due date so you'll have time to shop for items you didn't receive as gifts. Register for your shower if you haven't already done so.
Week 33 Interview baby nurses or postpartum doulas; locate a lactation specialist in case you need one later. Organize a support system of friends/family to help out when you're home with your new baby.
Week 34 Wash, fold, and put away all your baby clothes and install your infant car seat.
Week 37 Pack your bag for the hospital (don't forget your phone book). A baby is considered at term three weeks before your due date, so be prepared. Your doctor will want to see you every two weeks starting at weeks 36 and 37, then every week starting at week 38. At 36 or 37 weeks, your doctor will order a culture for Group B strep, an infection that can affect the baby. (If you do have Group B strep, you will likely be treated with antibiotics during labor.)
Week 38 If you plan to breastfeed, read up on techniques and gather resources to have at your fingertips when you come home. Join a local La Leche League group to meet the leader and other moms; you don't want to be a stranger if you need to call them for help. Buy nursing pads and bras.
Week 39 Many women begin maternity leave weeks before their due date. If you plan to work up until the end, post an "If I go into labor tonight" memo at work. If you'll be returning to work and plan to breastfeed, find or create a suitable place to pump.
Week 40 Relish these last days of feeling that little being moving and grooving inside your body. You won't believe how much you'll miss it.