Development tracker
Track your pregnancy
Find out how your baby is developing week by week with the Birth & Baby pregnancy tracker. Always remember that these milestones and developmental steps are just guidelines, but they will give you a good peek into your baby’s first room, the womb, and what is going down there.
First trimester
Weeks 1 to 12
Most of Baby’s development happens in the first trimester.
First trimester
Week 1
You aren’t pregnant yet, but your estimated due date is calculated according to the first day of your last period. This is considered week 1 of pregnancy.
First trimester
Week 2
Ovulation may occur this week. Believe it or not, your baby still hasn’t actually been conceived, although you are still technically pregnant.
First trimester
Week 3
Conception takes place in your fallopian tubes this week and the two cells that unite start dividing and growing rapidly.
First trimester
Week 4
The rapidly-growing embryo is dividing into inner and outer clusters and doubles in size every single day at this stage.
First trimester
Week 5
You may still not even know you’re pregnant, but the cells that will form Baby’s brain, vital organs, and digestive system have all formed.
First trimester
Week 6
By now, Baby is about 4mm long, and you can see him or her with the naked eye. You may even be able to hear a heartbeat.
First trimester
Week 7
Baby almost doubles in length, and the brain, which is the first organ to develop, grows by 25%. Leg buds also emerge this week.
First trimester
Week 8
This is a big week for Baby’s development. Baby is essentially a complete human being at this stage, although still tiny!
First trimester
Week 9
Baby may double in size this week, as the cartilage skeleton begins to be replaced by bone cells. Baby’s toes also start developing.
First trimester
Week 10
Baby’s heart is fully developed; it now has all four chambers, and it beats between 120 and 140 beats per minute!
First trimester
Week 11
Tiny fingernails start forming this week. Baby’s head also becomes rounder and is now almost half of Baby’s entire body size.
First trimester
Week 12
Baby can scrunch his little face, and all organs and systems found in a newborn are now present. Baby’s fingers and toes are all fully formed.
Second trimester
Weeks 13 to 27
Second trimester
Week 13
You’ve made it to the second trimester! Baby will now start changing posture, stretching and exercising their arm and leg muscles.
Second trimester
Week 14
Baby now has his or her own set of unique fingerprints and will respond to bright light through your abdominal wall.
Second trimester
Week 15
Baby’s individual footprints start forming on the soles of their feet this week! Baby may change position often, but you still won’t be able to feel this.
Second trimester
Week 16
By now, you may be able to identify Baby’s gender on sonar! Baby also starts growing hair, and tiny eyelashes start developing.
Second trimester
Week 17
Baby’s muscles become increasingly strong is he or she moves about. Some women can feel this, but mostly you won’t feel Baby’s movements just yet.
Second trimester
Week 18
By now you may be able to pick up on your baby’s sleep patterns. If you’re having a little girl, her ovaries will have already formed millions of eggs!
Second trimester
Week 19
Baby’s head circumference is about 16.4cm, and he or she will now begin to open and close their eyelids which have been closed since about Week 10!
Second trimester
Week 20
Baby, who has now reached about half his or her birth length, may begin to move whenever they hear your voice, Mom!
Second trimester
Week 21
Baby’s eye movement now becomes more sophisticated – his or her eyes can dart about or scan slowly. Baby may grasp and touch the umbilical cord often.
Second trimester
Week 22
It’s around this stage that you may start to feel Baby’s movement. At first, it may feel like little bubbles or butterflies in your belly.
Second trimester
Week 23
Baby now weighs about 450g and is covered in fine silky body hair called lanugo. This hair helps protect Baby is the womb.
Second trimester
Week 24
Baby’s eyes are now structurally complete and light-sensitive, and he or she will blink when they’re startled by loud noises!
Second trimester
Week 25
By now you should feel about 10 periods of movement a day, but these could still be quite gentle for another few weeks.
Second trimester
Week 26
Baby has now grown teeny little toenails and can nod and shake his or her head. Baby’s sense of smell also starts developing.
Second trimester
Week 27
Baby weighs about 1kg now and is 32cm long! He or she may start somersaulting in your womb, too – can you feel it?
Third trimester
Weeks 28 to 40
Third trimester
Week 28
Baby can now smell some scents that you do, Mom, and they’re able to tell the difference between sweet and sour tastes.
Third trimester
Week 29
Baby now weighs about 1,2kg. Every day, billions of neurons are being formed in Baby’s brain and central nervous system.
Third trimester
Week 30
This week, why not try to feel for Baby’s head through your belly? It will feel like a firm, smooth, rounded surface.
Third trimester
Week 31
The inner ear organs that help Baby to balance are now mature enough for Baby to control his or her own position in the womb.
Third trimester
Week 32
Fat layers are rapidly accumulating under Baby’s skin, making him or her all cuddly. Baby now weighs about 1,8kg and is about 45cm long.
Third trimester
Week 33
At this stage, Baby’s eyes move as if he or she is exploring your womb. Baby’s back is extremely flexible, allowing him or her to curl forward into the fetal position.
Third trimester
Week 34
Baby now weighs about 2kg and can tuck his or head so far forward that it reaches their hands at the abdominal level.
Third trimester
Week 35
By now, you should be able to see the skin creases on the palm of Baby’s hands. The brain continues to grow at a rapid pace.
Third trimester
Week 36
Baby starts gaining weight rapidly, and all the finishing touches start taking place as your due date draws steadily near.
Third trimester
Week 37
Baby may weigh as much as 3kg and be 50cm long. His or her skeleton starts to harden in preparation for birth.
Third trimester
Week 38
Baby’s movements may start to feel less vigorous as the womb becomes more cramped, but he or she should still follow their regular pattern.
Third trimester
Week 39
Baby’s head hair may be as long as 4,5cm by now, and his her skin will be very sensitive to touch all over their body.
Third trimester
Week 40
Fat layers will be deposited under Baby’s skin right up until you give birth. Hang in there, you’ll meet Baby any day now!
Natural, sensitive guidance in pregnancy, birth and family health, from the home of Sister Lilian since 1988.
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