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Fetal Development: How Does Your Baby Grow In The Womb?

fetal development stages

Congratulations! You are pregnant and like every other curious first-time mother - you sure would like to know all about the bodily changes to expect, baby growth stages, expected challenges in the first month of pregnancy, embryonic development, etc.

First, take a deep breath and relax! Pregnancy is the most fascinating journey; expect to be enthralled by it. There will be hormonal changes, cravings, mood swings yet it will be one of the most beautiful memories to cherish lifelong. A living being growing inside you- a baby in the womb! Mother Nature is fascinating indeed.

fetal development stages

Let me make it more exciting by unravelling the journey of baby development inside you - right from conception to birth.

Table Of Contents

1. Conception

2. Fetal Development Week By Week

3. Birth


fetal development stages conception

Conception happens the moment male’s sperm meets female’s egg. It penetrates and fertilizes it. This very moment, the genetic makeup of the baby to be born would be complete. Everything from the baby’s sex to the features have been decided and etched through the DNA. What begins next is the journey of fetal development, from embryo state to a fully fledged baby formation in the mother’s womb.

The fertilized egg, within three days from conception, would begin multiplying into cells extremely fast. The resulting mass would pass through fallopian tubes and reach the uterus. Here it attaches itself to the uterus lining and placenta begins to take shape. Placenta is the cord, connecting mother and baby, responsible for nourishing the developing baby.

The ground has been set, the environment created and now the actual baby growth in the womb will take place.

Keep reading further to know how your baby looks like during each growth stage:

Fetal Development Week By Week

As soon as the fertilized egg attaches itself to the uterus lining, a water tight sac begins forming around it that gradually starts filling with amniotic fluid. The sac, amniotic sac, is responsible for cushioning the baby during the complete pregnancy term.

Now let’s take a peek inside the womb to see how the baby develops week by week inside the womb.

Week 4

fetal development stages week 4

The first monumental stage, in fetal development week by week, is Week 4 when the embryo begins to take a formal shape. Face and neck begin forming; blood vessels and heart continue developing while stomach, liver and lungs start to develop. A home pregnancy testing kit, at this stage, would show positive results.

Week 8

fetal development stages week 8

At 8 Week old pregnancy, the baby in the womb would be about the size of half an inch. By now, as you see in the picture, legs and arms are well formed while eyes and ears begin to take form. The tiny tip of the nose can be seen. With time, toes and fingers would get more distinct and grow longer.

Week 12

fetal development stages week 12

At 12 Week old pregnancy, the baby in the womb would be about the size of two inches and will start making movements. Your baby’s heartbeat can be heard now with the doctor’s special instrument and the baby’s sex organs would start to become distinct. This is the stage where the child gains identity in form of either gender.

Week 16

fetal development stages week 16

By now the baby is anywhere between 4 to 5 inches in size and weighs around 3.5 ounces. Blood vessels and heart are fully formed and the baby can now even blink his/ her eyes. The baby has its own unique set of fingerprints now.

Week 20

fetal development stages week 20

At 20 Week old pregnancy, the baby in the womb is over 6 inches long and weighs around 10 ounces. Soon you will be experiencing ‘quickening’, that is you would feel the baby moving in your womb. Baby can now yawn, make faces and even suck a thumb. Isn’t that AMAZING?

This is also the time when your doctor would recommend your first ultrasound. Ultrasound shall be used to determine the health of baby growing inside the womb, baby’s position in the womb, his/ her heartbeat, movement of arms, legs and body, and the position of the placenta.

Week 24

fetal development stages week 24

The baby, at Week 24 of pregnancy, is around 1.4 pounds in weight and can respond to sound stimuli. The baby would respond to a variety of sounds, playing around the mother, by increasing or decreasing the pulse. Now we know, why our mothers have always insisted on listening to soothing music, hymns and positive songs/ prayers during pregnancy. The baby can hear from inside the womb!

Week 28

fetal development stages week 28

The baby, at Week 28 of pregnancy, is around 2 pounds and 5 ounces in weight and will begin changing position often in the womb. Intense care and attention are needed from this point of time right up to the delivery, as some women deliver pre mature baby during this phase. Usually, pre mature baby delivered at this stage can survive.

Stay in touch with your doctor and look out for premature labour warning signs. Take adequate rest. This is the perfect time to attend birth preparatory classes where experts shall prepare you physically and mentally for upcoming birth. You will gain valuable insights into what to expect during labour, delivery and immediately after birth as well as how to handle stress while caring for your newborn baby.

Week 32

fetal development stages week 32

At Week 32 of pregnancy, the baby development has reached the final stages where fat layer would start forming under the skin. The baby would be around 4 pounds in weight and will be making a lot of movement. A yellowish liquid, called as colostrums, may begin leaking from your breasts indicating the breasts are getting ready to make milk post birth. Visit your doctor every other week from this stage onwards.

Week 36

fetal development stages week 36

At week 36 of pregnancy, you are just a step away from birth. The baby would weigh anywhere around 6 pounds. Though baby’s size depends upon a variety of factors, including, parent’s genes, gender, and whether it is a set of twins or single baby etc. At 36- 37 week, the pregnancy is considered full term. Lungs are fully developed and the brain is rapidly developing.

Baby born between 37 – 39 weeks is early term baby; between 39-40 weeks is at/on term baby, and between 41-42 weeks is late term baby.


newborn baby boy

The onset of 40th week marks the end of pregnancy with a baby being delivered anytime soon. If there aren’t any signs of delivery, the doctor would induce labour. Ladies, please do not be afraid of delivery time, as soon you will be able to hold the most precious- the most miraculous creation of your own. Stay calm and let anxiety not get the better of you. You have completed the journey God intended for you. Relax and let nature take its course. Might sound difficult and unbelievable, but various studies have shown the birthing process to be less painful if the mother is calm, relaxed and cooperative with the doctor. Delivery pain is the prize any mother would pay for having a healthy baby of their own.

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