Baby’s Development inside the Womb

Babys Development inside the womb

Normal pregnancies last for 37 to 41 weeks, which means that your baby spends a lot of time in your womb. Read on to find out more about your baby’s development inside your womb and how it gradually grows into its full form, ready to see the world for the first time.

It is impossible to know the exact time that you conceived and that’s the reason doctor’s count the baby’s age from the first day of your last period. The entire time that your baby stays in your womb is known as gestation period. This means that during the first two weeks of your gestation period, you are not really pregnant. This is the time when your body is preparing to conceive a baby.

The First Few Weeks of Baby’s Development

In the first few weeks of your pregnancy, your body is just preparing to carry a baby. When your partner’s sperm enters one of your eggs, you conceive. This is the time when your conceived egg is called a zygote, and it spends several days travelling down the fallopian tube. This zygote constantly divides into numerous cells, which then turns into an embryo.

In the fourth week of your pregnancy, the ball of cells reaches the uterus, where it settles down on the uterine wall. This is the time when your uterus lining will thicken with blood, all set to carry a baby. During this week, the baby receives nutrition from the mother’s blood.

Week 5 – 10 of Baby’s Development: Baby’s Body Starts to Take its Shape

Once you enter into the fifth week of your pregnancy, your baby’s major systems and structures begin to develop. The cells of the embryo multiply and take charge of different functions in the body. Its kidneys, nerve cells, blood cells, all begin to form. The embryo is developing in speed at this point of time, and its external features take form.

The baby’s heart, spinal cord, and brain also develop at this stage. The embryo develops tiny buds that are the baby’s arms and legs. The brain further forms into five different portions, its tissues develop; the eyes and the ears also start to form. During week 6 and 7, your baby’s heart develops further, and your baby has a heartbeat now. The main vessels of the heart also begin to pump blood.

These are the most important weeks for your baby, as it is taking its actual form. Its main organs are also developing, and small details start becoming visible. Its hair, nipples, and eyelids develop, and its arms and legs elongate. The knees and elbows are also formed. When the first trimester ends, your baby is no longer an embryo, but it is now a fetus.

Babys Development inside the womb

Week 11 – 20 of Baby’s Development: The Embryo Turns into a Fetus

Your baby has now turned into a fetus as it has developed more organs. Its body is also beginning to take proper shape. This 5cm long fetus now has fingers, toes, and tiny nails. The fetus also develops its genitals, which defines your baby’s gender. When you enter the 14 week of gestation, your baby will begin to suck on its thumb. The baby’s body also gets covered in very fine hair, and its face takes a more human-like form. After the 16th week of your pregnancy, your baby will begin to make minor movements, but you will still be unable to feel it.

In your 20th week, your baby is almost 18 cm long. This is the time period when your baby’s muscles and bones begin to grow. It has also learned to make a fist and move its body slightly. The skin of your baby has also developed, but it is still transparent.

Week 21 – 30 of Baby’s Development: Better Proportioned Body

When you enter the 21st week of your pregnancy, your baby begins to come in proper proportions. Its eyelids are still closed and its small body is becoming well-proportioned to its big head. These are the weeks that your baby begins to hear different sounds from the outside world.  In the 28th week, your baby’s head begins to get covered with hair. Fat is also being deposited under its translucent skin, and its skin has also begun to plump.

Week 31 – 40 of Baby’s Development: The Final Days

Your baby has now entered into the final days of its time inside your womb. During the last ten weeks of your pregnancy, you will be feeling your baby moving around in the uterus and kicking you quite often. The baby’s eyelids will no longer remain close, and it will now be observing everything. Its senses are also more developed at this point. After the 36th week, your baby will move upside down, and its head will be right on top of the cervix. Your baby is now in its complete form. Its body is healthy and it is feeding properly through the placenta. The toenails and minor details begin to take their perfect shape and look.

The fingernails of your baby might also extend to the tips of its fingers, and its hair is coarser. The soft hair that covered your baby’s body will also disappear in the final days of your pregnancy.

During the last days of your pregnancy, your baby is fully formed, and ready to come into the world. A fully grown baby is about 44 to 55 cm, and weighs around 2.5 to 5 kg.  Your baby has fully functioning organs, and it is resting its head against your cervix, waiting for the right time to come out.

The entire pregnancy period is an amazing experience for the mother. The baby that was once the size of a grain of rice is now a fully formed human. The entire time that your baby stays in your womb is packed with ups and downs. A woman usually feels more uncomfortable during the first trimester when the baby is struggling to survive. This is the time when the mother needs to be most cautious and try to adopt a healthy lifestyle to avoid any birth defects and disorders.

Enjoy every moment of your pregnancy knowing that you will get to hold your very own baby after your gestation period is over.

© Teresa Boardman, Nanny Options.

Browse other Parenting Guide articles from Nanny Options
or keep up to date with us on Facebook.



Related Categories

Gift Vouchers

Gift Voucher Present
Gift Vouchers now available for all our services.

Members of NRF

Members of NRF

Other Parenting Guide Topics

Parenting Classes

Parents are eager to learn more about the range of baby products available.


A range of topics from food advice and sleeping to Signs of labour and giving birth. 


A collection of articles to support you and help you understand your newborn better.