Fetal Development

By DubbTN
  • Week 1

    Week 1
    This is the last menstrual period of the female. The beginning of the menstrual bleeding is the first day of pregnancy.
  • Period: to

    Fetal Development

  • Week 2

    Week 2
    3 to 10 eggs are maturing and preparing for ovulation. The endometrium is thickening up to form a sack that will carry and protect the baby. Sperm is trying to penetrate the egg to fertilize it. Chromosomes are going to combine and determine the physical traits of the baby
  • Week 3

    Week 3
    During this time the fertilized egg begins dividing, and the gender is determined.
  • Week 4

    Week 4
    The fertilized egg is knowkn as a blastocyst- a fluid filled cluster of 60-60 cells. hCG is release into your bloodstream after the blastocyst is implanted to increase physical pregnancy signs.
  • Week 5

    Week 5
    Embryo doubles in size egg becomes muccus membrane of uterus. Placenta starts developing and embryo recover nutrition and oxygen through placenta.
  • Week 6

    Week 6
    Embryo becomes 1/4 inch, spinal cord begins to close, first blood cells and blood vessels develop, heart is formed and begins beating, brain develops into 5 parts, optic cavaties and appendage cells are in place to be developed.
  • Week 7

    Week 7
    Embryo is now 1/2 inch, heart beats with 1 chamber, arms and legs begin to grow, jaw and vocal cords begin forming the lungs, the liver, the pancreas, and the thyroid gland begin forming.
  • Week 8

    Week 8
    Embryo is now 3/4 inch, elbows and toes are becoming visible, starts practicing movements, stomach is being made and face is taking shape.
  • Week 9

    Week 9
    Embryo is 1.2 inches, nose tip, tongue and larynx begin to form. The heart is now complete.
  • Week 10

    Week 10
    Embryo becomes a fetus the size of a strawberry. The neck begins to take shape, body muscles are almost done developing, baby begins moving, fingerprints are formed, nipples and hair follicles begin to form.
  • Week 11

    Week 11
    Fingers and toes completely seperated, tastebuds develop, baby can stick out tongue and swallow. Most of the body is sensitive to touch. (If gender is male, testicles start producing testosterone.)
  • Week 12

    Week 12
    Fetus is 2.5 inches, starts moving spontaneously. Face begins to look like a baby face, pancreas produces insulin, the fingernails and toenails appear, baby can suck thumb and get hiccups baby can feel pain.
  • Week 13

    Week 13
    Fetus is 3 inches, bones replace cartilage, external genitalia is almost defined.
  • Week 14

    Week 14
    The fetus in now 3.5 inches long. The face is starting to become more visible and the baby is peeing. Bones are getting stronger and harder and hair is starting to develop.
  • Week 15

    Week 15
    The baby is 4 inches long. The legs and arms are growing longer than the head. The skin is very thin and the bone marrow is developing throughout the skeletal sysem.
  • Week 16

    Week 16
    The fetus is 5 inches long. The temperature is regulated, the fetus can breathe, and can hear voices externally. Facial muscles are developed and can be used to make expressions.
  • Week 17

    Week 17
    The baby is 9 inches if it stretches. The eyes are sensitive to light and the baby can poop. Fat is developing under the skin so the baby has energy and warmth after birth.
  • Week 18

    Week 18
    Protective layer is forming on the baby's skin. It can hear sounds, and has sleep patterns of a newborn. They have a favorite position to sleep in.
  • Week 19

    Week 19
    Placenta is growing and the heart is visible thourgh ultrasounds. The baby's genitals are devloping.
  • Week 20

    Week 20
    This is the halfway mark through pregnancy. The baby can hear voices and be familiarized with them. Growth of hair on the rest of the body is starting.
  • Week 21

    Week 21
    The baby's bone marrow is creating blood cells. The baby is slowly increasing weight due to the fat being added to the body.
  • Week 22

    Week 22
    The eyebrows, eyelids, and fingernails are developed. The tongue's tasetbuds are forming.
  • Week 23

    Week 23
    The baby is now 11 inches tall, weighs about a pound and is proportional. It can sense its direction inside the womb due to the inner ear. The pancreas is starting to produce insulin for the baby to break down sugars.
  • Week 24

    Week 24
    The baby's lungs are developing bronchioles and the baby is breathing in the amniotic fluid. The muscles in the baby's hands are improving so they can suck their thumb
  • Week 25

    Week 25
    The structure of the spine is beginning to form all the rings, joints, and ligaments. The nostrils are opening, reflexes are developing, and the nerves are more sensitive.
  • Week 26

    Week 26
    The baby is responding to touch and is very active in the womb. The baby is going through the breathing movements, but no air is actually going inside the lung.
  • Week 27

    Week 27
    This is the start of the third trimester and the look of the baby will be the same at birth. The brain is rapidly growing, and the retina of the eyes are developing.
  • Week 28

    Week 28
    The baby is now entering REM sleep and the eyelids can open now. If this baby was born prematurely they have a 90% chance of living.
  • Week 29

    Week 29
    The head of the baby is growing bigger due to the brain developing billions of neurons. The baby has more forceful movements and the mom can feel it.
  • Week 30

    Week 30
    The baby's bone marrow is producing red blood cells that are transporting oxygen and getting rid of waste. The baby is getting fatter because its storing fat.
  • Week 31

    Week 31
    The baby's major organs are functioning, the growth of the baby will now focus on maturing these organs and adding muscle mass. Loud noises may scare te baby.
  • Week 32

    Week 32
    The baby sleeps a lot. If the baby is a boy the testicles are moving towards the scrotum, and for a girl baby the clitoris is projecting.
  • Week 33

    Week 33
    Lanugo is disappearing and hair is replacing it. The baby is drinking amniotic fluid beacues its practicing breathing.
  • Week 34

    The baby's head is now in position for birth. The arms and legs are plump due to the fat.
  • Week 35

    Week 35
    Baby's reflexes are coordinated and responds to sounds, light and touch. The baby is getting very fat.
  • Week 36

    Week 36
    The baby is very chubby now due to the fat layers. The baby dropped into the birth canal and is ready for birth.
  • Week 37

    Week 37
    The baby is 19.5 inches and weighs up to 7 pounds. The water could break at anytime.
  • Week 38

    Week 38
    The baby is 20 inches and weighs 7.5 pounds. The development is complete and now the baby focuses on gaining weight and the soft down is now disappearing
  • Week 39

    The baby is in the final birthing position. The baby is in the uterus for movement.
  • Week 40

    Week 40
    This is the final week of pregnancy and can happen at anytime. The contractions can begin in any moment.