Pregnancy Follow-up: Baby Development During Pregnancy Week by Week

Pregnancy Follow-up: Baby Development During Pregnancy Week by Week

Pregnancy week starts on the first day of the last menstrual period, which occurred 2 weeks ago . Therefore, the first 2 weeks of pregnancy do not yet mean anything for the development of the baby. Remember, the following weeks are the weeks of the development of the fetus in the womb.

In the meantime, let’s also point out that just as development differs from child to child, the same is true for the unborn baby. So these are average values, if you can’t find the exact value, please don’t worry.

If you want to read about your pregnancy, one of the most special periods of your life, in full detail: Journey to the Day of Birth from a Poppy Seed: Baby in the Womb!

1. Baby Development in the Mother Womb in the Trimester

During the first trimester of pregnancy, ie the first trimester, you will experience the happiness and excitement of being pregnant and try to get used to this new situation. Early pregnancy symptoms will make you feel bit by bit. During this period, your baby will begin to form gradually.

1st Trimester: The First Trimester of Pregnancy

1. Week

This week, the baby’s height is 0.150 mm and his size is the tip of a pin.


The baby’s height is around 0.36-1mm, the size of a poppy seed. Placenta, germinal layers, brain, hair and skin are formed. The liver, pancreas and thyroid division are developing. The skeleton, connective tissues, blood system, urogenital system and most of the muscles are formed.

1. and 2. Weeks

3. Week

The baby is 1.25 mm long, the size of a sesame seed. The layer that will form your heart is developing. Brain, spinal cord, muscle, bone structures, skeleton are taking shape.

3-Week Pregnancy

4. Weeks

The baby is 2mm-4mm long and the size of a lentil. As an embryo consisting of head and tail. Neural tubes are closed, the first brain chambers and eyes are formed, organ buds appear, heart cavities merge.

4 Weeks Pregnancy

5. Weeks

4mm-5mm long, about the size of a blueberry. Leg buds appear like short fins, arm buds are growing, hand and arm-shoulder sections are separated, finger points in hands and feet bud, heart protrudes, the first bronchus is formed in the lungs, the hemispheres that form the brain develop, the eyes and nostrils are formed, the intestines develop.

5 Weeks Pregnancy


It has small movements but of course not what you can feel. Arms bend at the elbows over the heart.

6 Weeks Pregnancy

7. Week

Your baby is 2.2 cm-3 cm long, the size of an olive grain. His arms and legs are lengthened, his fingertips are widened, the head is straightened, the eyelids cover the eyes, the outer auricles become prominent.

7-Week Pregnancy

8. Week

3.1 cm-4.2 cm height and 5 grams weight. Almost as small as a plum. At the end of this week, the embryo turns into a fetus. Three cell layers are formed, the development of fetal organ systems begins. It looks like a human.

8 Weeks Pregnancy

9. Weeks

4.4 cm-6 cm long and 8 grams in weight, about as little as a lemon. His head is half the size of his body. His chin is separated from the chest, the neck is extended, the fingernails on the fingers are extended. External reproductive organs are beginning to be distinguished.

9 Weeks Pregnancy

10. Week

The baby is 6.1 cm long and its weight is 8-14 grams. Her fingers and toes are separated, her nails grow.

External reproductive organs are starting to give clues about sex. The small intestine contracts little by little and becomes able to absorb glucose. The pituitary gland is starting to produce many hormones.

Heartbeat may begin to be heard. It moves through the uterus but is not noticeable. When stimulated from certain points, it can open its mouth and move its fingers and toes.

10 Weeks Pregnancy

11. Weeks

He is 6.5-7.8 cm tall and weighs 13-20 grams. Head growth slows down. Her face looks more like a human. The eyes formed on the sides of the head are getting closer. Ears take their normal place. External reproductive organs develop enough to be gender-discriminated. The intestine slips into the abdominal cavity.

11 Weeks Pregnancy

12. Week

At the end of the first trimester, your baby is 8-9.3 cm tall and weighs 25 grams, almost the size of your fist. The eyes continue to move towards their intended positions and the neck continues to grow. The chin no longer rests on the body. Gender development continues.

12 Weeks Pregnancy

2. Baby Development in the Womb in the Trimester

In the second trimester, you will get over the early period symptoms more easily as a mother-to-be who is accustomed to pregnancy.Your baby will grow at a tremendous speed. It will make you feel with kicks and punches.

2. Trimester: Second Trimester of Pregnancy

Tests Performed During Pregnancy: Which are the 2nd Trimester Tests?

13. Week

At the beginning of the second trimester, the baby is 9.3-10.3 cm long and weighs 50 grams. Thinning his skin. Fine hairs called lanugo cover his body. His eyes continue to move towards their places. His ears continue to develop. Their bones get stronger and they accumulate calcium. His skeleton becomes visible.

13 Weeks Pregnancy

14. Weeks

10.8-11.6 cm long and around 80 grams. Lanugo feathers cover his head. The umbilical cord slips down the body. Nails on their hands are completely formed. His legs are longer than his arms.

His arms and legs can move. During this period, you may feel your movements.

14 Weeks Pregnancy

15. weeks

The baby is 11-12 cm tall and weighs 100 grams. Fat formation begins. His movements become more noticeable. It can suck and swallow.

15 Weeks Pregnancy


He may hiccup and yawn.

16 Weeks Pregnancy

17. Week

Your baby’s height is 13-15 cm this week, and his weight is around 200 grams. Her skin is covered with a varnish material to protect it from amniotic fluid. Their kidneys can produce urine. He can start to hear voices. He may be involved in conscious muscle movements such as thumb sucking and moving his head.

17 Weeks Pregnancy

18. Week

14-16 cm long and 260 grams in weight. If her gender is a girl, her uterus is completely shaped and the vaginal canal begins to develop. If it is a man, his testicles go down his stomach. Her skin is getting thick. Her hair and nails continue to grow.

She can turn, curl, kick and punch.

18 Weeks Pregnancy

19. Week

18 cm tall and 300 gr weight. It’s starting to taste this week. His arms and legs find the right proportion. Connecting neurons between the brain and its muscles. Cartilage tissues are starting to turn into bone.

19 Weeks Pregnancy

20. Week

The baby is 19 cm long and weighs 350 grams. Eyelids are developing.

The reproductive system continues to improve. The vagina of the girl is formed. The uterus and ovaries settle. If he is a man, his testicles continue to descend towards the scrotum.

This week he can touch his face and limbs and suck his finger.

20 Weeks Pregnancy

21. Week

Height is 20 cm and weight is 455 grams. Your baby is getting chubby but his skin is still wrinkled. Lanugo hairs are getting darker. Her face and body look like a baby at birth. The veins in your lungs continue to grow to prepare for breathing. She continues her irregular movements.

21 Weeks Pregnancy

22. Week

It is 21 cm long and weighs 540 grams. Her eyelashes, eyebrows and hair are completed. His inner ear is developing. You may feel your movements more because of the blood sugar that rises after eating. He can kick hard.

22 Weeks Pregnancy

23. Week

His height is 22 cm and his weight is 700 grams. Their capillaries are formed and filled with blood. Air sacs form in his lungs. Nostrils are starting to open. The vocal cords are starting to work. He hiccups begins the first breathing attempts.


Your baby is 23 cm long and weighs 910 grams this week. His eyes are starting to open. Eye color is not clear, there is no pigment. It creates a sleeping-waking order. 5 sense organs are fully developed. It gets more active in bright light or loud sound.

24 Weeks Pregnancy

25. Week

24 cm long, 1 kilo. The taste buds are developing. Eyelids open. Their kicks and movements vary according to the food. Their movements can generally be reduced. She can open and close her eyes.

25 Weeks Pregnancy

26. Week

Height is 25 cm and weight is 1.1 kg. Brain tissue increases, pits and grooves form on the surface of the brain. Her hair is growing. Fat ratio is increasing. He has a 20-30 minute sleep pattern. He can blink, cough, suck his finger, sob, breathe.

26 Weeks Pregnancy

27. Week

At the end of the second trimester, her height is 26 cm and her weight is 1.25 kg. It continues to get fat and plump. It moves less because its space is constrained. Still, he can hit hard with his elbows.

27 Weeks Pregnancy

The most enjoyable time to go shopping for pregnant women: Honeymoon of Pregnancy: 2.

Baby Development in the Womb in the Trimester Symptoms will reappear in the last 3 months as you approach delivery. You will enjoy the happiness of carrying a real baby in your womb (Goodbye beans). As the birth approaches, your worries and excitement may increase, a little more patience.

3. Trimester: Last 3 Months in Pregnancy

28. Week

With the third and last trimester, her height is 27 cm and weight is 1.35 kg. His brain is developing, lanugo hairs are beginning to fall out. Movements may be irregular.

28 Weeks Pregnancy

29. Week

Height is 28 cm and weight is 1.6 kg. If it is a man, his testicles move next to his testicles. The girl’s clitoris becomes more prominent. His lungs and brain are well developed. REM sleep is starting to sleep. He can follow the light. Her movements are in order.

29 Weeks Pregnancy

30. Week

reached a length of 29 cm and a weight of 1.8 kg. Due to its oily skin, its skin is no longer transparent. Quince feathers are shedding to a large extent. Movements and kicks are reduced.

30 Weeks Pregnancy

31. Week

Height 30 cm, weight 2 kg.

When he is active and calm, he is now in routine.

31 Weeks Pregnancy

32. Week

Length 32 cm, weight 2.28 kg. The varnish layer that protects your skin begins to thicken. Her nails reach her fingertips. There is no significant difference in her movements.

32 Weeks Pregnancy

33. Week

33 cm, 2.5 kg. Brain cells continue to increase. His head grows faster. As the ground becomes narrower, his movements decrease, but you may feel tense, rolling and wiggling. His head can turn towards the pelvis.

33 Weeks Pregnancy

34. Week

Height 34 cm, weight 2.75 kg. The digestive system is ready. He continues to store fat, his face is quite round. Usually it takes a stable position.

34 Weeks Pregnancy

35. Week

35 cm tall, 2.95 kg weight. He prepares for the first breath, draws amniotic fluid into his lungs and empties them. Sucking her thumb, blinking her eyes.

35 Weeks Pregnancy

36. Week

Height 35 cm, weight 3.1 kg. Lanugo is almost completely free of hair and varnish.


The baby is 36 cm long, 3.25 kilos this week. He is waiting to be born. Usually little movements.

37 Weeks Pregnancy

Weeks 38, 39, 40

Now we have come to an end. Its height is 38 cm and its weight is 3.4 kg. Born, will be born! Usually less movements.

38 Weeks Pregnancy

39 Weeks Pregnancy

40- 41 ​​Weeks Pregnancy

Final steps: Last Months of Pregnancy: 7 Things You Need in the 3rd Trimester



Written by Lady Byron


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