Pregnancy Development

The Pregnancy Development Stages

A new life starts when just one sperm cell from the male joins and fertilizes an egg cell from the female. Just moments after conception numerous hereditary characteristics are determined. These include the different features and individual trademarks such as gender; color of eyes, hair and skin; the shape of the face and body; and certain qualities of temperament and intelligence.

Week 1

  • My cells begin dividing as I travel along your fallopian tube.
  • In these cells are the blueprints for my development—hair and eye color, height and sex.

Week 2

  • The cells have now divided into three layers: The inside layer will become my breathing and digestive organs. The middle layer will develop into bones and muscles, circulatory system, kidneys and sex organs. My outside layer will become my skin and nerves.

Week 3

  • I am now attached to the wall of your uterus.
  • My brain is starting to take shape.

Week 4

  • My heart is beating.
  • My backbone and muscles are forming.
  • My eyes are beginning to show.

Week 5

  • I have arms and legs.
  • My brain waves can be detected and recorded.
  • My nose and mouth are beginning to show.

Week 6

  • I have little fingers.
  • My heart is beating twice as fast as yours.

Week 7

  • I’m moving around now.
  • My mouth can open and I have lips and a tongue.
  • My toes are stubby.

Week 8

  • My home is about the size of a hen’s egg now.
  • I’m a little more than an inch long.
  • All my major organs are working—my heart, brain, lungs and kidneys, liver and intestine, although not fully developed.
  • I can even feel!

Week 9

  • My vocal cords are developing.
  • I even have taste buds.
  • The development of my eyes is complete.

Week 10

  • I am now 1 ½″ long (they measure me from the top of my head to my little bottom).
  • My ears are almost fully developed.

Week 11

  • I get hiccups now.
  • I know how to swallow.
  • I can even turn my head and make facial expressions—I can frown, squint, and wrinkle my forehead, and I am 2″ long!

Week 12

  • My home (the ovum) is the size of a tennis ball.
  • I am swimming and exercising every day.
  • I can curl my toes and make a tight fist.
  • I’m kicking you now but you probably can’t feel it.
  • Your clothes are probably starting to get tight now.

Week 13

  • My mouth, nose and external ears are completely developed.
  • I am 3″ long and weigh one ounce.

Week 14

  • My hair is growing.
  • I’m developing my muscles and exercising energetically.
  • I’m growing up quick—I’m now 4″ tall and weigh over 2 ounces, maybe the doctor will let you hear my heartbeat.

Week 15

  • I have eyebrows, eyelashes, and some “fluff” on my head.
  • I can probably hear your heartbeat, your stomach rumbling, and the sweet sound of your voice.
  • I am over 5″ long.

Week 16

  • I enjoy drinking a lot of the fluid when it is sweet, but not when you’ve eaten something sour.
  • I can turn somersaults!
  • I yawn and stretch.
  • I’m 6″ long.

Week 17

  • I’m getting my finger and toe nails.
  • My skin is developing.
  • My sex can be seen by ultrasound if I pose just right.
  • I’m now 7″ tall!

Week 18

  • I can hear sounds outside of your body—if it’s loud, I’ll jump!
  • I like testing my reflexes, kicking and punching with well-formed arms and legs (you may begin to feel me now).

Week 19

  • If you haven’t felt me kicking by now, maybe you will this week.
  • I’m drinking a lot. The liquids that surround me are always fresh because they are replenished every 6 hours.
  • I am now 9″ long.

Week 20

  • I’m kicking and moving around a lot, so you better get used to it!
  • I’m 10″ tall and weigh a little more than 8 ounces.

Week 21

  • I have a special skin that protects me in the womb but it will dissolve before you see me.
  • I am now 11″ long and weigh just under a pound.

Week 22

  • You may feel a jerking motion but don’t worry, it’s just me with hiccups!
  • You should begin to notice my responding to sound—I like it when you sing.

Week 23

  • Creases have begun to appear on my fingertips and the palms of my hands.
  • You can hear my heartbeat through a stethoscope, or, if someone puts their ear against your tummy.

Week 24

  • I’m reacting more to sound—I’ll move in rhythm to music I hear.
  • I’m 13″ tall now.

Week 25

  • My hands are active now.
  • I’m starting to fatten up!
  • I can even cry!

Week 26

  • I’m probably dreaming when I sleep.

Week 27

  • I can open my eyelids and look around, it’s not always dark in here since bright sunlight or artificial light can filter through to me.
  • If I were born now and given proper care I could survive.

Week 28

  • It’s beginning to get a little cramped in here and I’m having a harder time moving around.
  • I’m 15″ long and weigh in at two pounds!

Week 29

  • My heart rate increases when I hear your voice!

Week 30

  • I almost fill up all of the space in your womb.
  • It’s time for me to stand on my head.

Week 31

  • I’m moving less because there’s no room in here!
  • I’m all curled up with arms, legs and knees bent… and you think you’re uncomfortable!
  • I’m 16″ tall and weigh about 3 lbs, 3 ozs.

Week 32

  • If I’ve turned to the head-down position, you’ll feel my feet against your rib cage.

Week 33

  • I’m still a little on the thin side, but perfectly formed!
  • My moving may make you uncomfortable… it’s crowded in here!
  • I measure 16″ long.

Week 34

  • When I practice my breathing I swallow fluid which gives me hiccups!
  • I’m practicing my blinking.
  • My hair is growing and could be 2″ long.
  • I respond to other familiar voices now.

Week 35

  • I’m getting plumper… better make room!
  • I’m 17″ tall and weigh about 5 pounds, 5 ounces.

Week 36

  • I’m almost ready… if I were born now, I’d do just fine.
  • I measure 18″ long.

Week 37

  • My toenails and fingernails have grown out.

Week 38

  • I can tell the difference between light and dark… I see more in the light!

Week 39

  • My skin is soft and smooth.
  • My body has filled out.
  • I’m 19″ long and ready to go!

Week 40

  • Ready or not, here I come!


The growth pattern described above is recognized medical information, documented by scientific research. Slight variation in development days may exist from individual to individual.