The development of your baby in the womb week-by-week

If you are a first-time mom, you may be wondering how your baby grows throughout your pregnancy journey. In this article, we compile everything you need to expect in the development of your baby in the womb week by week.

Baby in womb week by week: How to count pregnancy weeks?

You may be asking how to count pregnancy weeks, and the answer is here! Counting pregnancy weeks starts from the first day of your last period. According to NHS UK, this means that in the first 2 weeks, you are not pregnant yet but rather your body is preparing for ovulation.

Counting pregnancy weeks: Timeline of pregnancy

The timeline of pregnancy starts on the first day of your last period. Next, on day 14 ovulation takes place. Within 24 hours of ovulation, implantation will happen where the fertilized egg attaches itself to the walls of the uterus. And this is when your pregnancy starts.

How many weeks of pregnancy or how many weeks of pregnancy until the baby is delivered?

We all know that pregnancy takes 9 months until the baby is born, so how many weeks for pregnancy or how many weeks of pregnancy are 9 months? The pregnancy cycle human takes 40 weeks until the baby is delivered.

In this article, we discuss the week by week stages of pregnancy from week 1 up to week 40.

Pregnancy cycle of human from week 1 to week 40

Baby in womb week by week: Week 1-2

During weeks one and two you are not yet considered pregnant but your body is then preparing for ovulation. At this point, your uterus is getting ready for the arrival of a fertilized egg.

Pregnancy week by week: Week 3

In the third week, the fertilized egg is moving toward the uterus along the fallopian tube. When the fertilized egg reaches the womb, it will become an embryo. When the embryo attaches itself to the uterine wall then the implantation will happen.

Pregnancy symptoms week by week 

At week 3, when the implantation is successful you may notice a tiny bit of spotting called implantation bleeding. It is a normal process of the body and nothing to worry about.

Aside from that, you may also notice changes in your vaginal discharge. From thick, sticky, and creamy, it will now become thin, and gooey and will increase in volume. Other pregnancy symptoms at week 3 are as follows:

• Tender and swollen breast
• Fatigue
• Heightened sense of smell
• Higher basal body temperature

Pregnancy week by week: Week 4

At week 4 the amniotic sac is now present. Aside from that, the yolk sac is also present at this time. The amniotic sac will serve as your baby’s home until birth while the yolk sac is responsible for delivering all nutrients to your baby in the womb.

Pregnancy symptoms week by week

You may experience bloating due to increased levels of progesterone hormones. In addition, you may also have some mild cramps. And because your hormones are fluctuating, mood swings are expected.

Pregnancy stages week by week: Week 5

At week 5, your baby’s major organs such as kidneys and liver are starting to grow. Moreover, your baby’s heart is beginning to divide into chambers. Other parts of their body will start to develop too such as the intestines, appendix, and neural tube. At this point, your baby looks more like a tadpole than a human.

Symptoms of 5 weeks pregnant

You may experience soreness of the breasts, morning sickness, and fatigue in week 5. Another symptom of 5 weeks of pregnancy is the frequent urge to pee due to expanding kidneys.

Pregnancy stages week by week: Week 6

Your baby’s heart is now beating and pumping blood. Their circulatory system is developing and their facial feature is evolving from looking like a tadpole to a more human form.

Symptoms of 6 weeks pregnant

• Feeling lethargic and exhausted
• Mood swings
• Morning sickness
• Sore breasts

Baby in womb week by week: Week 7

At week 7 your baby is now about a size of an aratilis or the Singapore cherry. Their nervous system is developing and now generating about 100 new brain cells per minute. The brain and heart of your baby are becoming complex while the permanent set of kidneys is developing. Aside from that, the arm and leg joints are starting to form at this stage and the hands and feet are slightly emerging.

Symptoms of 7 weeks pregnant

• Constant urge to pee
• Acne breakouts
• Skin changes from oily to dry or vice versa
• Varicose veins
• Nausea
• Food cravings

Week by week stages of pregnancy: Week 8

From the size of an aratilis, your baby is as size as a red bean kidney at this time. At week 8 the facial features are becoming more defined including the ears, upper lip, and nose. Additionally, the tadpole-like tail is starting to disappear during this stage.

Symptoms of 8 weeks pregnant

• Heightened sense of smell
• bigger and heavier breasts
• fatigue and nausea
• pregnancy cramps
• indigestion or constipation
• bloating
• heartburn

Baby in womb week by week: Week 9

At week 9, your baby is no longer an embryo but rather a fetus. The facial features are more recognizable and it looks less like a tadpole and more like a human. At this stage, your baby’s heartbeat can now be detected through ultrasounds. The embryonic tail is now completely gone and their nipples and hair follicles are forming.

Moreover, all the major organs like the heart, brain, lungs, and kidneys begin to develop during this period. Also, the bones are now starting to build up.

Symptoms of 9 weeks pregnant

• thickening waistline
• bloating
• fuller breasts
• darker nipples
• morning sickness
• fatigue
• backaches
• loss appetite
• inability to focus

Week by week stages of pregnancy: Week 10

All your baby’s vital organs such as the kidneys, intestines, brain, and liver are now in place and functioning. Their fingers and toes are now formed and tiny fingernails are starting to emerge. Furthermore, their bones are starting to harden and take shape.

Symptoms of 10 weeks pregnant

• noticeable veins in the breasts and abdomen
• pain in the belly
• weight gain
• increased vaginal discharge
• heartburn
• food cravings
• sensitive sense of smell
• bloating

Baby in womb week by week: Week 11

The ears, lips, nose, and eyelids of your baby are now developed at week 11. Your baby is growing quickly and the placenta is rapidly developing. At this stage, the facial bones are formed.

Symptoms of 11 weeks pregnant

• sore breasts
• fatigue
• frequent urination
• heartburn
• lesser morning sickness
• headaches and mood swings

Week by week pregnancy: Week 12

12 pregnancy weeks to months is 3 months. At this period, you are now 3 months pregnant, the last week of your first trimester. Your baby’s organs and tissues are in rapid growth and start to develop reflexes. Your baby at week 12 can now curl their fingers and toes. Aside from that they can now close and open their tiny hands. The fingernails and toenails begin forming and the taste buds are maturing.

Symptoms of 12 weeks pregnant

• noticeable brown patches on the face or neck
• visible linea nigra, the brown line starting from your belly button through your pubic area.
• weight gain
• mild cramps

Baby in womb week by week: Week 13

Your baby’s eyes and ears are now well-defined. Their legs and arms are lengthening and becoming proportionate. All the baby’s essential organs and systems are formed and fully functioning. At week 13, the genitals are forming outside of the body and the testes or ovaries are fully developed. Furthermore, at this period, your baby’s heartbeat is loud and clear.

Symptoms of 13 weeks pregnant

• reduced fatigue and nausea
• a renewed sense of energy
• discomfort around the ribcage area

Week by week pregnancy: Week 14

Week 14 is an exciting week of pregnancy. Your baby can now smile, frown, and grimace. Aside from that, they can now taste bitter, sweet, or sour flavors in the amniotic fluid. The roof of their mouth is completely formed and their hair is now growing on top of their head. At this period, your baby may try to suck their thumb or wiggle their toes. Their kidneys are beginning to make urine.

Symptoms of 14 weeks pregnant

• more prominent baby bump
• increased energy levels
• regained appetite
• backaches and abdominal pain
• thicker and shinier hair

Pregnancy week by week chart: Week 15

Eyebrows and hair start to appear this week. At this point baby’s body is becoming more proportionate. Aside from that, your baby’s lanugo will start to shed to acquire baby fats.

Pregnancy symptoms week 15

• lowered immunity
• possible nose bleed and bleeding of the gum
• weight gain

Baby in womb week by week: Week 16

At week 16 your baby is the size of an avocado seed. The baby will be busy strengthening their muscles at this time. Further development will happen such as they have now the ability to frown or squint. At this stage, the eyebrows and eyelashes are fully developed. Your baby’s sense of hearing begins to develop at week 16.

Pregnancy symptoms

• feeling breathless at times
• may begin to feel the movement of the baby
• constipation
• hair and nails start to grow faster

Pregnancy week by week chart: Week 17 

Instead of amniotic fluid, your baby’s air passage is now ready to take in oxygen. The nerves are now forming myelin while the bones have started hardening. At this stage, your baby’s umbilical cord is becoming thicker and stronger.

Pregnancy symptoms

• weight gain
• stretch marks
• increased vaginal discharge, sweat, and mucus

Baby in womb week by week: Week 18

Your little one is as size as a sweet potato at this time. Your baby is now moving and can roll, tumble, and flex its limbs in your womb. In addition, they can now yawn and their hearing is well-developed.

Pregnancy symptoms

• feeling hungry every few hours
• swollen feet and hands
• backache
• increased pressure on the veins of your nose that may result in a nosebleed

Weekly pregnancy development: Week 19

Your baby at this period weighs the same as a mango. At 19 weeks, your baby is now developing the protective layer of its skin. Add to that, the skin is beginning to develop pigments. Their hair is growing and the lanugo covers their entire body. Their sense of smell, taste, hearing, vision, and touch is now blossoming.

Symptoms of pregnancy at week 19

• round ligament pain
• dizziness
• leg cramps
• headaches
• trouble sleeping
• UTI
• Heartburn
• Bloating and diarrhea

Baby in womb week by week: Week 20

At week 20 your baby is a size of a banana. The baby can now suck their thumb, twist and turn inside the uterus, yawn, blink, and react to outside stimuli like music and loud noises. Furthermore, their skin is now thickening and developing layers. The vaginal canal, if you are expecting a girl, or the testicles if you are having a boy, is now developing.

Symptoms of 20 weeks pregnant

• Weight gain
• Interrupted sleep
• Fatigue and morning sickness faded away
• Increased vaginal discharge
• Back pain
• Increased appetite
• Shortness of breath
• Slightly swollen hands and feet
• Varicose veins
• Bloating and flatulence

Weekly pregnancy development: Week 21

The intense movement of the baby can be felt by this time. Their eyebrows and eyelids are now fully formed and allow them to blink. Their taste buds can now taste a variety of flavors.

Symptoms of pregnancy at week 21

• The belly is big enough to look pregnant
• Stomach tightening
• Stretch marks
• Pregnancy acne
• Varicose veins
• Headaches and backaches
• Swollen hands and feet
• Nosebleed
• Leg cramps

Counting pregnancy weeks: Week 22

What exciting about week 22 of pregnancy is that your baby is now practicing how to breathe even if they are still in your womb. Aside from that, the eyebrows, eyelashes, lips, and fingernails are now fully developed. Moreover, if your baby is a girl, her vagina is fully developed by now. Also, the pancreas is now producing important hormones while other organs continue to grow.

Symptoms of Pregnancy

• Abdominal pain
• Bloating and constipation
• Varicose veins
• Dizziness
• Leg cramps or round ligament pains
• Diarrhea
• Pelvic pressure
• Braxton Hicks
• Increased libido
• Increased vaginal discharge

Baby in womb week by week: Week 23

The fine hair called lanugo that covers the baby’s body may darken by week 23. Your baby’s eyes are completely formed. However, the eyes do not have color yet while the ears have developed a stable hearing sense. Moreover, the area in the brain responsible for sensing movement is now developing.

Symptoms of 23 weeks pregnant

• Swollen ankles and feet
• Backaches
• Bleeding or swollen gums
• Braxton hicks

Timeline of pregnancy: Week 24

Your baby at week 24 is the size of a corn cob. In this period, your baby’s face is now completely formed. The ears are now in place and can pick up clearer sounds. Aside from that, their taste buds are now fully developed while their brain is growing rapidly. Furthermore, their lungs are developing branches and the respiratory tree.

Symptoms of week 24 pregnant

• Weight gain
• Heartburn
• Skin changes
• Round ligament pain
• Dizziness
• Carpal tunnel syndrome

Baby in womb week by week: Week 25

By this time, your baby can hear and distinguish your voice. They may even respond when you talk to them by moving. Your baby’s movement will become routine and their skin is now turning pink. At week 25, the first bowel movement of your baby will happen but it will only come out when they are born.

Pregnancy symptoms

• Lower back pain
• Body aches
• Itchy veins in your rectum
• Constipation
• Bloating

Week 26

Your baby can now open its eyes and its hearing system is completely formed. Aside from that, the air sacs of the lungs or the alveoli are now completely developed.

Symptoms

• Extremely protruding baby bump
• Backaches
• Heartburn
• Leg cramps
• High blood pressure

Week 27

Your baby’s ability to hear is getting stronger at week 27. At this point, your baby can now respond to the food you consume. You might feel belly spasms if you try spicy food. It is because your baby is having a hiccup.

Pregnancy symptoms

• Braxton Hicks contraction
• Mild swelling of ankle, feet, and hands
• Swelling or bleeding gums
• Restless leg syndrome

Week 28

Your baby can now sense light from the outside. They may turn their head in your uterus when they notice a bright light shining from the outside. Their bones at week 28 are nearly developed. However, their bones are still soft. Meanwhile, their lungs are now mature enough.

Pregnancy symptoms

• Hemorrhoids
• Leg cramps
• Constipation
• Sleeping problem

Week 29

At week 29, your baby’s head is now growing to accommodate its growing brain. The baby’s muscles and lungs continue to mature while their auditory ability improved greatly. Moreover, if your baby is a boy, his testicles are moving from their location tucked up near his kidneys down through his groin. On the other hand, if your baby is a girl, her clitoris is fairly prominent.

Symptoms

• Severe pain and unintentional loss of urine due to the baby’s kicks and punches
• skin rashes, dryness, and intense itching due to hormonal changes
• mood swings
• fatigue
• weight gain

Week 30

The soft, downy hair covering your baby’s body is now disappearing. Meanwhile, their brain and new fat cells regulate their body temperature. Aside from that, their bone marrow has taken over the production of red blood cells. The digestive tract is nearly mature at week 30.

Symptoms

• Morning sickness and mood swings may return
• Painful heartburn

Week 31

Your baby’s organs continue to develop and their arms, legs, and body now proportion with their head. They can now identify light from the darkness. Your baby will continue to move, make faces, and hiccups, swallow, breathe, and kick.

Symptoms

• Occasional headaches
• Frequent urination
• Getting more forgetful

Week 32

Your baby at week 32 will continue to swallow, breathe, kick, and suck their thumb. Their digestive system is now matured and their skin is becoming more opaque. You may feel your baby’s decrease in movement, it is because your baby is sleeping well these days.

Symptoms

• Swelling belly
• Painful spasms
• Heartburn
• Pregnancy cramps

Week 33

Your baby’s immune system is developed and they have learned how to breathe now. The bones in their body are hardening and they are undergoing some major brain development. Aside from that, your baby can now differentiate between night and day.

Symptoms

• Feeling overheated
• leg cramps
• anxiety
• headaches
• heartburn
• pain in the belly
• shortness of breath
• forgetful

Week 34

Excessive fat layers are now developing on your baby’s body. It is necessary to keep them warm. Moreover, the central nervous system is now developing faster while their fingernails and toenails have grown.

Symptoms

• Fatigue
• Increased vaginal discharge
• low blood pressure
• dizziness and blurry visions
• feeling breathless
• leg cramps

Week 35

In this period, your baby is continuously gaining the necessary weight. You may feel frequent kicks from your baby. Moreover, your baby’s kidneys and liver are fully developed now while their brain power is developing at a tremendous rate.

Symptoms

• heartburn and gastrointestinal problems
• frequent urination
• occasional headaches
• skin rashes
• mild contractions or Braxton Hicks

Week 36

The lanugo hair that covers your baby’s body and the waxy coating protecting them in the womb is now shedding off. The baby will start to move towards your pelvis and realign himself in the head-down position. Their blood and immune system are now fully developed.

Symptoms

• Worst backache
• Bloating and constipation
• Thick vaginal discharge
• Difficulty walking
• Itchy belly
• Braxton Hicks contractions

Week 37

Your baby is considered full-term when you reach the 37th week of pregnancy. Your baby’s head is now surrounded and protected by your pelvic bones. They no longer have lanugo and their hair is up to 3.5 cm long. Thumb sucking is their favorite pastime around this stage. They will roll, stretch, and wiggle more.

Symptoms

• Uncomfortable weight in the belly
• Anxiety
• Increased vaginal discharge

Week 38

Most of your baby’s organs are fully developed and in place by now. His nails have been growing at week 37.

Symptoms

• Swollen feet and ankles
• Breasts may begin leaking a thin yellowish liquid called colostrum
• Uncomfortable feeling on the legs and vaginal area.

Week 39

Your baby at week 39 is breathing well and their brain continues to develop. The nails may extend past their fingertips. What’s more exciting is that your baby’s cheeks are becoming kissable and pinchable. The thicker layer of fat deposited over his blood vessels causes their skin to turn white.

Symptoms

• False labor now and then
• Urge to clean and tidy up your space

Week 40

Finally! Your baby is yet to make his way through the birth canal. You will continue to feel uncomfortable as your baby makes his way down your pelvis.

Symptoms

• Sharp pains in the abdomen, vaginal area, and along the legs

There it is mommies, a complete guide for your pregnancy journey week by week. Above all, it can also help you to get ready to the things you might experience to your pregnancy journey. 

Here at theAsianparent Philippines, it’s important for us to give information that is correct, significant, and timely. But this doesn’t serve as an alternative for medical advise or medical treatment. theAsianparent Philippines is not responsible to those that would choose to drink medicines based on information from our website. If you have any doubts, we recommend to consult your doctor for clearer information.