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Week One
Week one of a 40 week pregnancy is marked by the first day of a woman's menstrual bleeding. It also marks the last menstrual period. -
Week 2: Fertelization
The uterus starts to prepare the body lfor ovulation. In the days leading up to ovulation, the eggs produced are ripened in the follicles and the endometrium is becoming thicker. On the day of ovulation, the egg goes into the fallopian tube where a sperm cell will fertilize with it. -
Week 3: Cells divide...New life begins!
After the egg becomes fertelized, it begins to divide while floating down into the uterus. During this, depending on the chromosomes of the sperm from the father, that will decide if the baby will be a boy or girl. The egg continues to divide at a fast tempo while going down the fallopian tube into the uterus where it then becomes burrowed in the lining. -
Week 4: Implantation
The egg becomes a blastocyst where it will go through implantaion when the placenta attaches to the uterine wall. Then the blastocyst will release hCG to singnal the lining of the uterus to not shed like it does during menstruation. -
Week 5: The embryonic stage
The amniotic fluid will pile up and the egg will become a mucous menbrane which protects the umbilical sac and the fluid cavity. The placenta gives the embryo oxygen and nutrition while the a sheet of cells behind the embryo folds in the middle which forms the spinal cord. -
Week 6: Body parts are forming
During this week, all the major body organs and systems have started to take shape like the ears, sides of the head, and the heart. Though they are not fully developed, the heart begins its first beat on the 25th day after conception. -
Week 7: More systems and limbs form
As with the week prior, more of the baby's organs and systems begin to develope. This time the arms and legs take shape, parts of the stomach form, and also major organs like the lungs and kindneys. -
Week 8:
Nothing really new happens this week, just more development of limbs but facial begin to form. Aside from that, arms and legs still continue to grow but the most important thing about this week is that the baby starts to move. Although it's practicing, so it's in the early stages. -
Week 9: Fingers and toes form
Still the same old routine as previous weeks with some minor additions. The fingers and toes are now formed, the larynx is starting to take shape, the brain is growing very fast making it larger than the body, and the heart has completed shaping. -
Week 10: Embryo is now a Fetus
By this week the developing child has evolved into a fetus. In addition, the body muslces are nearing completion and now the neck has started to form. -
Week 11: Neurons multiply
250,000 nerve cells are formed a minute by a rapidly forming brain. New things have started developing like taste buds, genitals, and cartliage can now identify as bone. Also the baby can do new functions such as swollow, stick out his/her tounge, and body becomes sensitive to touch. -
Week 12: Fingernails and toenails appear
At this week a lot of new changes happen to the baby like having it's fingernails and toenails fully developed. Also the face starts to look like a actual face, the baby is now able to suck its thumb and hiccup along with moving more and more. -
Week 13: Baby flexes and kicks
By this week the baby is now 3 inches and weighs 1 ounce. In addtition, new abilities are learned like flexing/kicking, opening its mouth, and the body can produce insulin. -
Week 14: Hormones start up
More and more changes are still happening like the baby being able to pee into the amniotic fluid aroung itself and start learning to breath. Depending on what gender the baby is, the boys now have prostate glands while girl's ovaries move to the pelvis. -
Week 15: Bones and muscles grow
The baby still continues to learn new skills like move its limbs and make a fist. Now this time around, the legs have finally out grown the arms and the body becomes longer than the head. However, the bones and muslces still need to grow more. -
Week 16: Facial expressions are possible
New abilites continue to be learned and used by the baby such as breathing, squinting/frowning, and somersault. Due to better breathing, the lungs gain a boost in its development process. -
Week 17: Fat accumulates
This is a big week for the baby's fat since fat stores start creation beneath the skin. This will provide energy for the baby and keep it warm. In addition, the umbilical cord becomes more thicker and stronger. -
Week 18: Baby begins to hear
Another big week for the baby's development since it's now able to hear. This means the baby can be alarmed by lound noises. Also the baby can notice active and rest periods and begans to have sleep patterns/positions. -
Week 19: Genitals are recoginizable
Based on the baby's gender, it will either develope a uterus or if a boy, the genitals are then distanct. In other news, the legs have alomst reached their normal size and more muscle growth happens. -
Week 20: The halfway point
This weeks marks exactly the midway point of the 40 week process. At this point in time the baby has developed hearing outside noises like voices, music, and sounds. It can react to them and the senses are becoming more and more stronger since nerve cells are being made in the brain. -
Week 21: Nourshment evolves
More changes are evolved like blood cells being produced by bone marrow and the body is now able to absorb small amounts of sugar. This is thanks to the small intestine. -
Week 22: Taste Buds develop
This week, the new things for the baby are being able to hear if a person talks or sings and react to them if the outside noise is long enough. The taste buds have also formed on the tounge and the baby develop a sleep routine. -
Week 23: Sense of balance develops
The baby's inner ear is fully developed and now the baby has balace control. This causes the baby to make a workout routine by turining side to side and head over heal. Also the baby can tell if it's upside down or not. -
Week 24: Practices breathing
The baby is now improving its breathing through development of branches from the lungs. They produce surfactant which assists the air sacs inflate easily and keep the samller ones from collapsing. -
Week 25: Exploration continues
Nothing major happens aside from different body organs and nerves either improving or nearing completion. For instance, the sexual organs have developed fully and brain cells are starting to mature. -
Week 26: Second trimester ends
The baby is becoming more active by being able to move its limbs more. They have also developed a sense of touch and this week is the last week of the second trimester which will lead into the final third. -
Week 27: Eyes can open
New changes come this week with the baby being able to blink and control its eyes to open and close. Also the brain and hearing still continue to improve. -
Week 28: May recognize your voice
The baby gains some new abilities this week such as eye movement in sleep. This could mean that the baby is able to dream. In addition, could start to recognize the mother's voice a little better when she reads, talks, or sings. -
Week 29: Movement is more forceful
With the head increasing to make the right amount of space for the brain, billions of neurons are made. The eye sockets can move and movement becomes harder since the baby is getting bigger but the womb remains the same. Also, the baby can tell the diference between sounds. -
Week 30: Baby puts on pounds
Baby is gaining more and more weight each week. It weighs about three pounds this week, however, it will gain about half a pound a week until week 38. In addition, some features become fully developed like the hands. -
Week 31: Baby detects light
Nearly all major organs are near completion so they will start on maturing. Also, the baby may began to move to the beat of the song. Furthermore, the irises in the eys can react to light, like dilat and contract. -
Week 32: Reproductive development continues
Movement has decreased from the baby because it sleeps most of its days around this time of year. The baby will however try to move but the limited space makes if difficult. Changes in genitals happen whether if the baby is a boy or girl. -
Week 33: Lanugo is dissappering
Several new changes happen like the baby using its lungs to practice a new technique for breathing by inhailing amniotic acid. The baby also starts to drink a pint of amniotic fluid a day. Also the baby's head start to grow hair on its head because the lanugo starts to dissapper. -
Week 34: Rapid growth continues
The arms are plumped due to fact accumulation. The baby is also developing an immune system due to antibodies crossing through the placenta. In additions, the fingernails are completed and the baby has a chance of survival of born early. -
Week 35: Reflexes are coordinated
Layers of fat help keep body temperature at a constant state inside the womb. The lungs are fully completed and the baby is able to coordinate movement of the head, grasp, and respond different senses. -
Week 36: Baby may drop into birth canal
The mother's body may be feeling contarctions at this point. So far the only organ that has to mature is the lungs of the baby. There is also a slight chance a baby may drop into the birth canal in the birth position preparing for the due date. -
Week 37: Pregnancy is considered 'a term'
The baby is almost ready to come out. Although, it's considered at "term" because the baby could come out anywhere from now or the due date. Contractions will start and the baby's limbs would start to stretch from the stomach. -
Week 38: Development is complete
As the 40 week process is coming to an end, the baby's is now fully developed. Its only job now is to gain weight to help regulate body temperture after its born. In addition, the baby should have a full head of hair at this point. -
Week 39: Almost time
The baby is in the postition it will take up when he/she is being born. At this time the baby's movements may not be as forceful since he/she will be in the uterus where it's less cramped. -
Week 40: Due Date
Now it's now or never for the baby, he/she will be in the fetal position while its in the birth canal. Everything in the baby has fully developed , all organs and limbs and he/she weighs 6 to 9 pounds. In addition, the baby will squirm more and kick less until its time for it to come out where its heart and lungs would adapt to the air outside the womb.
