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Week 1
This is the first day of your menstrual period. It is difficult to pinpoint the actual day of fertilization so week one starts from the first day of your last menstrual period before pregnancy. -
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Fetal Development Timeline
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Week 2
This is when ovulation occurs. An egg is released and this is where the sperm meets the egg and is fertilized in the fallopian tubes. -
Week 3
The fertilized egg begins to divide and then floats down into the uterus. The sex of the baby is determined immediately upon fertilization, this is based on the father's sperm chromosomes. -
Week 4
During this time, the embryo implants itself into the uterus. The fertilized egg is now labeled as a blastocyst because it is a cluster of 50-60 cells filled with fluid. -
Week 5
At week 5, you may be suspecting you are pregnant. Hormones are being produced by the embryo which stops the mother's menstrual cycle. -
Week 6
The heart of the embryo begins to beat. The size of the embryo is still smaller than a raisin at this point. -
Week 7
The arms, legs, and major organs being to form in the embryo. The embryo is now about the size of a blueberry. -
Week 8
Facial features including ears, nose, mouth, and eyes begin to develop. This is when the mother will start having their first prenatal visits. -
Week 9
The fingers and toes are forming along with the main construction of the heart is complete. The baby is now swimming in a little bag of fluid. -
Week 10
The embryo has now become a fetus. Although it cannot be felt, the fetus is moving around within the mother. -
Week 11
The baby has small teeth inside the mouth and can move and stick-out its tongue. It is about the size of a lime. -
Week 12
Fingernails and toenails are starting to appear. The baby may suck its thumb. The brain is fully formed and the baby can feel pain. -
Week 13
The baby starts to flex and kick within the womb. Insulin is being produced and its fingerprints are fully developed. -
Week 14
More hormones in the baby's body beings to start up. The genitalia is fully formed and the kidneys are producing urine. -
Week 15
It is now officially the second trimester of pregnancy. The bones and muscles continue to form and grow. The baby is about the size of an apple. -
Week 16
The baby has officially learned to breathe. It can also make different facial expressions. The baby is about the size of an avocado. -
Week 17
Fat begins to store under the baby's skin. The eyes are now looking forward, but are remained shut. -
Week 18
The baby can now hear sounds within the mother or even loud noises from outside. A protective layer is forming around the fetus. -
Week 19
The baby's genitals are recognizable and so this is when the doctor will reveal the sex to the parents if wanted. Scalp and body hair are continuing to grow. -
Week 20
This marks the midpoint of the pregnancy. The baby's heart can be heard with a stethoscope and the skin is thickening. The baby is about the size of an artichoke or banana. -
Week 21
The baby has steadily gained weight. The small intestine is absorbing sugars and the bone marrow is producing blood cells. -
Week 22
The baby can actively hear what's going on. Loud noises and sudden movements can wake or bother the baby. Taste buds on the tongue have also begun to form. -
Week 23
A sense of balance has developed as it will do some kind of "workout" within the mother's womb. The eyebrows are visible and the bones in the middle ear begin to harden. -
Week 24
Breathing practices begin as the baby's lungs continue to strengthen. If the baby were to be born now, it is somewhat likely that they would survive. -
Week 25
The body is now proportionate and continues to grow. The sexual organs are fully developed. The baby is about the size of a cauliflower. -
Week 26
The baby's hands are very active and fully developed. The eyes also may begin to open. The baby is very active. -
Week 27
The third trimester has officially begun. The baby's eyes can open, close, and blink. At birth, the baby may look similar to how it does now just larger. -
Week 28
The baby may be able to recognize the sound of your voice. There is now a regular pattern for sleep and being awake. The hair on the head is clearly visible. -
Week 29
Movements from the baby are much more forceful and are capable of being felt. The fetus can taste things and respond to pain. -
Week 30
At this time, the baby puts on lots of weight. The baby can also regulate its own temperature. The baby is about the size of a cabbage. -
Week 31
The baby can now detect light as the eyes have fully opened. Loud noises may also cause the fetus to jump or squirm. -
Week 32
During this time, the baby doesn't have much to do so it sleeps for most of the day. The mother will not experience much movement because the space has simply become too small for big movements. -
Week 33
The baby fuzz, or lanugo, is disappearing. The baby drinks about a pint of amniotic fluid a day. It is common for the mother to gain about a pound a week for the rest of her pregnancy. -
Week 34
The rapid growth of the baby continues. The skin becomes less wrinkled and the eyes close when sleeping and open when awake. There are excellent chances of survival if the baby was born now. -
Week 35
The reflexes of the baby are now coordinated. The body of the fetus is becoming round due to the developing fat layers. The baby is about the size of a honeydew. -
Week 36
The baby's body is becoming chubby and is gaining about an ounce a day. It may drop into the birthing canal. -
Week 37
The pregnancy is now considered "at term." The water could break at any time and the head diameter is over 9 centimeters. -
Week 38
The development of the baby is complete. The baby is in an upside-down position with the feet facing upwards. The soft down is now disappearing. -
Week 39
The baby has reached its final birth position. It is very cramped inside the mother's uterus. The baby is about the size of a watermelon. -
Week 40
The mother has reached the time of delivery. It is now just a matter of time and the contractions could begin at any time. Congrats!
