Fetal Development

  • Week 1

    Female goes through her last menstrual period. This is day 1 of pregancy and only about 43 more weeks to go
  • Period: to

    First Trimester

  • Week 2

    Week 2
    The sperm has met the egg in the fallopian tube. The egg has turned into a secondary oocyte because it is now fertilized.
  • Week 3

    Week 3
    The fertilized egg now beings divideing into 2 cells, then 4 cells and so on. The cells begin to grow into a blastocyte and start making its way down the fallopian tube.
  • Week 4

    Week 4
    The many cells are now a Blastocyte and have floated down into the uterus. In the next few hours-days the blastocyte will float around the uterus for a while until it eventually embeds itself onto the endometrium.
  • Week 5

    Week 5
    The embryo now starts the process of shaping into a human. The placenta is developing and amniotic fluid begins to build up whcih will surround the fetus. The embryo is about 2-5mm.
  • Week 6

    Week 6
    The embryo is beginning to form their main organs. The spinal cord begins to start closing, the brain begins to divide into its lobes, arms and legs are growing and the heart beat starts to play.
  • Week 7

    Week 7
    We are half way into the first trimester. The small details are begining to form around the face such as the nose, the nasal string, the mouth opening. vocal cords also begin to form and other major organs liek the lungs are growing
  • Week 8

    Week 8
    The embryo now has little arms and legs in place, fingers and toes are visible. It is about 18mm and it begins to practice movement.
  • Week 9

    Week 9
    Embryo starts growing bones and cartiliage. Now has a fully developed and working heart. Eyelids are begining to show however will not open for many weeks later.
  • Week 10

    Week 10
    Embryo is now called a Fetus. Muscles are almost finished developing and fingerprints on skin are begining to form.
  • Week 11

    Week 11
    Fingers and toes are seperate. Fetus can awallow and stick out tongue. Gender is begining to be defined.
  • Week 12

    Week 12
    Fetus' face is starting to look like a human baby. Nails start appearing. Pancreas begins to function and fetus can hiccup and suck thumb
  • Week 13

    Week 13
    First Trimester ends. Baby starts to replace carto;age and ribs start forming and being visible. Baby starts moving more noticable.
  • Period: to

    Second Trimester

  • Week 14

    Week 14
    Second Trimester starts. Kidneys are functioning, producing urine. Sex is continuing to be formed weather the ovaries are moving to the pelvis or prostate gland begins forming. Eyes are making their way up to the center of the face.
  • Week 15

    Week 15
    Fetus' skin is very fragile. Arms are able to make fist. Muscles are getting stronger as they continue to develoepe.
  • Week 16

    Week 16
    Baby is able to smile and make other facial expressions. Senses start functioning, baby is soon able yto recognize mothers voive, sleeps and dreams
  • Week 17

    Week 17
    Umbilical cord begins to get thicker and fetus starts gaining weight. Fetus' digestive system starts functioning and preparing to poop for the first time.
  • Week 18

    Week 18
    Baby now starts to hear and can be startled nby loud noises/ Aveoli start to form. May start sleep patterns like regular newborn
  • Week 19

    Week 19
    Hair is begining to grow in the scalp. Sex is able to be recognized if in right position.
  • Week 20

    Week 20
    Woman is half way done with pregnancy. Body hair has begain to grow such as on arms and legs. Heartbeat is able to be heard without an ultrasound through a stethoscope.
  • Week 21

    Week 21
    Bine marrow starts producing blood cells. Small intestine starts functioning and abosrds sugar. Due date is able to be estimated based on size of head.
  • Week 22

    Week 22
    Taste buds start to develope on tongue. Fetus starts establishing a regular sleeping schedule.
  • Week 23

    Week 23
    Fetus can suck thumb with no problem. Inner ear helps with controling balance. Pancreas developes.
  • Week 24

    Week 24
    Week 24 is the stage where the baby has the best possiblity to start living outside the womb with the proper care. Baby gains about 3 oz per week
  • Week 25

    Week 25
    Bones are nearly solid and hard. Sex organs have finished developing. Fetus' npstrils start to slowly open.
  • Week 26

    Week 26
    Second Trimester Ends. Fetus is able to respond to touch. Fetus can breath but no air is able to go in lungs.
  • Period: to

    thirtd Trimester

  • Week 27

    Week 27
    third Trimester begins. Fetus is now able to open eyes however still not able to see.
  • Week 28

    Week 28
    Hair is visible through 4D ultrasounds. Milk teeth have started growing under the gums and eyes start to move.
  • Week 29

    Week 29
    Fetus' movements can be easily felt by mom. Can respond to pain and is sensible to light. Lungs strart to mature.
  • Week 30

    Week 30
    Fetus can control its body temperature. If male, testies have moved down to the groin. Eyebrows and Eyelasyes start growing on the face. Uterus is about 4 inches above the bellybutton.
  • Week 31

    Week 31
    eyes are able to respond to light and dark. Fetus begins to jump and kick mom.
  • Week 32

    Week 32
    Diameter of head is nearly or about 4 inches. Fat is growing under the skin.
  • Week 33

    Week 33
    Lanugo is starting to go away. Fetus starts praticing breating by inhaling amniotic fluid.
  • Week 34

    Week 34
    Eyes can be open if the baby is awake. Baby skin starts smoothing out. Contractions for mom can get stronger and more painful.
  • Week 35

    Week 35
    Lungs are nearly fully developed. Baby has many reflexes ae=re more coordinated. Baby can survive well is born this week.
  • Week 36

    Week 36
    There is a big chance baby has dropped into birth canal. Dialation starts occuring in these next few weeks and birth can happen any day.
  • Week 37

    Week 37
    Moms water is at a high possibilty of breakiing. Pregnancy is conseriderd at term at this point since the baby is going to arrive any one of these days.
  • Week 38

    Week 38
    if fetus has not yet reached birth canal, they might have now reached the birth canal position. Babys body fat starts building up even more.
  • Week 39

    Week 39
    If baby hasnt been born yet, you are 1 week away from 40 weeks. Baby is in birth canal position. Langugo has completely gone away. Baby should weigh about 7 lbs.
  • Week 40

    Week 40
    Contractions can go from hours to minutes apart. Baby should be born any day during this week. Baby will push until it has deached the lower abdomin.