Prenatal Development

  • Week 1

    Week 1
    Days 1-7 of development. Uterus is preparing for fertilization.In the first week of your pregnancy, there's no baby--yet.But a growing fetus will be there.
  • Period: to

    week 1-41 of pregnancy

    pregnancy- conception through birth
  • Week 2

    Week 2
    Fertilization. Your baby's sex has already been decided, and their major organs are all beginning to form.
  • Week 3

    Week 3
    fetus has started on its miraculous transformation from solitary cell to bouncing baby boy or girl. Once the winning sperm makes its way through the egg's outer layer, the single-cell fertilized egg — or zygote — immediately forms a barrier to keep other sperm out.
  • Week 4

    Week 4
    baby is an embryo the size of a poppy seed, consisting of two layers: the epiblast and the hypoblast, from which all of her organs and body parts will develop.
  • Week 5

    Week 5
    Deep in your uterus your embryo is growing at a furious pace. At this point, he's about the size of a sesame seed and looks more like a tiny tadpole than a human. He's now made up of three layers – the ectoderm, the mesoderm, and the endoderm – which will later form all of his organs and tissues.
  • Week 6

    Week 6
    babys head takes shape.Facial features (like eyes and nostrils) are beginning to form, and little buds appear where arms and legs will develop.
  • Week 7

    Week 7
    Your baby's hands and feet are emerging from developing arms and legs – although they look more like paddles at this point than the tiny baby fingers and toes you're daydreaming about holding and tickling.
  • Week 8

    Week 8
    Your baby's hands and feet are developing webbed fingers and toes, his eyelids almost cover his eyes, breathing tubes extend from his throat to the branches of his developing lungs, and his "tail" is just about gone.
  • Week 9

    Week 9
    the baby is size of a grape, nearly a inch long. Your baby's organs, muscles, and nerves are kicking into gear. The external sex organs are there but won't be distinguishable as male or female for another few weeks. Her eyes are fully formed, but her eyelids are fused shut and won't open until 27 weeks. She has tiny earlobes, and her mouth, nose, and nostrils are more distinct.
  • Week 10

    Week 10
    size of a kumquat. a little over an inch or so long, crown to bottom – and weighs less than a quarter of an ounce, your baby has now completed the most critical portion of his development. This is the beginning of the so-called fetal period, a time when the tissues and organs in his body rapidly grow and mature.
  • Week 11

    Week 11
    just over 1 1/2 inches long and about the size of a fig – is now almost fully formed. Her hands will soon open and close into fists, tiny tooth buds are beginning to appear under her gums, and some of her bones are beginning to harden
  • Week 12

    Week 12
    Your baby's fingers will soon begin to open and close, his toes will curl, his eye muscles will clench, and his mouth will make sucking movements. intestines, which have grown so fast that they protrude into the umbilical cord, will start to move into his abdominal cavity about now, and his kidneys will begin excreting urine into his bladder.
  • Week 13

    Week 13
    Fingerprints are forming on your baby’s tiny fingertips, her veins and organs are clearly visible through her still-thin skin, and her body is starting to catch up with her head – which makes up just a third of her body size now.
  • Week 14

    Week 14
    Your baby can now squint, frown, grimace, pee, and possibly suck his thumb! Thanks to brain impulses, his facial muscles are getting a workout as his tiny features form one expression after another. His kidneys are producing urine
  • Week 15

    Week 15
    Your growing baby now measures about 4 inches long, crown to rump, and weighs in at about 2 1/2 ounces about the size of an apple. you may be able to find out whether your baby's a boy or a girl. Although her eyelids are still fused shut, she can sense light. If you shine a flashlight at your tummy, for instance, she's likely to move away from the beam
  • Week 16

    Week 16
    he's about the size of an avocado: 4 1/2 inches long (head to rump) and 3 1/2 ounces. His legs are much more developed, and his head is more erect than it has been. started growing toenails
  • Week 17

    Week 17
    baby's skeleton is changing from soft cartilage to bone, and the umbilical cord – her lifeline to the placenta – is growing stronger and thicker baby weighs 5 ounces now, and she's around 5 inches long from head to bottom. She can move her joints, and her sweat glands are starting to develop.
  • Week 18

    Week 18
    baby is about 5 1/2 inches long, and he weighs almost 7 ounces (about the size of a bell pepper). He's busy flexing his arms and legs his ears are now in their final position
  • Week 19

    Week 19
    brain is designating specialized areas for smell, taste, hearing, vision, and touch. Some research suggests that she may be able to hear your voice now,
  • Week 20

    Week 20
    baby weighs about 10 1/2 ounces now. He's also around 6 1/2 inches long from head to bottom and about 10 inches from head to heel – about the length of a small banana.
  • Week 21

    Week 21
    baby now weighs about three-quarters of a pound and is approximately 10 1/2 inches long – about the length of a carrot. You may soon feel like she's practicing martial arts as her initial fluttering movements turn into full-fledged kicks and nudges.
  • Week 22

    Week 22
    At 11 inches and almost 1 pound (about the size of a spaghetti squash), your baby is starting to look like a miniature newborn. His lips, eyelids, and eyebrows are becoming more distinct, and he's even developing tiny tooth buds beneath his gums.
  • Week 23

    Week 23
    more than 11 inches long and weighs just over a pound (about the size of a large mango),Blood vessels in her lungs are developing to prepare for breathing
  • Week 24

    Week 24
    baby is growing steadily, having gained about 4 ounces since last week. That puts him at about 1 1/3 pounds. Since he's almost a foot long about the length of an ear of corn
  • Week 25

    Week 25
    baby now measures about 13 1/2 inches. Her weight – 1 1/2 pounds – isn't much more than an average rutabaga, but she's beginning to exchange her long, lean look for some baby fat.
  • Week 26

    Week 26
    nerves in your baby's ears is better developed and more sensitive than before.Your baby is continuing to put on baby fat. He now weighs about 1 2/3 pounds and measures 14 inches (about the length of a scallion) from head to heel.
  • Week 27

    Week 27
    baby weighs almost 2 pounds (about the size of a head of cauliflower) and is about 14 1/2 inches long with her legs extended. She's sleeping and waking at regular intervals, opening and closing her eyes, and perhaps even sucking her fingers.
  • Week 28

    Week 28
    baby weighs 2 1/4 pounds (about the size of a large eggplant) and measures 14.8 inches from the top of her head to her heels. She can blink her eyes, which now sport lashes. With her eyesight developing, she may be able to see the light that filters in through your womb.
  • Week 29

    Week 29
    baby now weighs about 2 1/2 pounds (about the size of a butternut squash) and is a tad over 15 inches long from head to heel. His muscles and lungs are continuing to mature, and his head is growing bigger to make room for his developing brain
  • Week 30

    Week 30
    Your baby is about 15.7 inches long now and weighs almost 3 pounds (about the size of a large cabbage). A pint and a half of amniotic fluid surrounds her, but that volume will shrink as she gets bigger and takes up more room in your uterus.
  • Week 31

    Week 31
    baby measures over 16 inches long. He weighs about 3 1/3 pounds (about the size of a coconut) and is heading into a growth spurt. He can turn his head from side to side, and his arms, legs, and body are beginning to plump up as needed fat accumulates underneath his skin
  • Week 32

    Week 32
    baby weighs 3 3/4 pounds (about the size of a large jicama) and is about 16.7 inches long, taking up a lot of space in your uterus. You're gaining about a pound a week and roughly half of that goes right to your baby
  • Week 33

    Week 33
    baby weighs a little over 4 pounds and has passed the 17-inch mark (about the size of a pineapple). He's rapidly losing that wrinkled, alien look, and his skeleton is hardening. The bones in his skull aren't fused together, which allows them to move and slightly overlap, thus making it easier for him to fit through the birth canal
  • Week 34

    Week 34
    baby now weighs about 4 3/4 pounds (about the size of a cantaloupe) and is almost 18 inches long. Her fat layers – which will help regulate her body temperature once she's born
  • Week 35

    Week 35
    Your baby doesn't have much room to maneuver now that he's over 18 inches long and tips the scales at 5 1/4 pounds (about the size of a honeydew melon
  • Week 36

    Week 36
    baby is still packing on the pounds, at the rate of about an ounce a day. She now weighs almost 6 pounds and is more than 18 1/2 inches long ,about the length of a head of romaine lettuce. She's shedding most of the downy covering of hair that covered her body
  • Week 37

    Week 37
    due date is very close now, but doctors don't consider your baby "full term" until 39 weeks. Spending the next two weeks in the womb allows your baby's brain and lungs to fully mature.
  • Week 38

    Week 38
    baby has really plumped up. She weighs about 6.8 pounds and is over 19 1/2 inches long (about the length of a leek). She has a firm grasp, which you'll soon be able to test when you hold her hand for the first time! Her organs have matured and are ready for life outside the womb.
  • Week 39

    Week 39
    baby is full term this week and waiting to greet the world! He continues to build a layer of fat to help control his body temperature after birth, but it's likely he already measures about 20 inches and weighs a bit over 7 pounds, about the size of a mini-watermelon
  • Week 40

    Week 40
    the average newborn weighs about 7 1/2 pounds (about the size of a small pumpkin) and is about 20 inches long. Her skull bones are not yet fused, which allows them to overlap a bit if it's a snug fit through the birth canal during labor
  • Week 41

    Week 41
    baby may now weigh almost 8 pounds and stretch a bit over 20 inches long. As cozy as he is, your baby can't stay inside you forever. For safety reasons, your doctor or midwife will talk with you about inducing labor if your baby isn't born in the next week