Pregnancy is an incredible journey where your body goes through many changes as it nurtures the life growing inside you. As the weeks pass, you may start to wonder what’s happening inside the womb. Here’s a look at fetal development week-by-week:
Week 1 to 2: Conception and Implantation
During the first week, your baby-to-be is just a single cell. However, by the end of the second week, your baby has already implanted in your uterine lining and started the process of cell division.
Week 3 to 4: Beginning of Organs
At this point, your baby is the size of a poppy seed. The heart, brain, spinal cord, and digestive system begin to form, along with tiny buds that will become arms and legs.
Week 5 to 6: Limbs and Facial Features
By week five, your baby is the size of an apple seed. Arm and leg buds start to resemble paddles and tiny fingers and toes begin to form. By week six, facial features like the eyes, ears, and nose are beginning to take shape.
Week 7 to 8: Rapid Growth and Development
Your baby is now the size of a blueberry at seven weeks and a raspberry at eight weeks. During this time, the brain is growing rapidly, and the baby’s facial features become more defined. The tiny fingers and toes also become separated.
Week 9 to 10: Fingernails and Hair
By week nine, your baby is the size of a cherry, and fingernails and hair follicles start to form. By week ten, the baby’s tailbone disappears, and it becomes officially classified as a fetus.
Week 11 to 12: Refinement and Movement
During this period, your baby’s facial features continue to refine. The baby starts to move its limbs, and its fingers and toes can flex. The fetus also starts to produce urine, which it releases into the amniotic fluid.
Week 13 to 14: Senses Develop
By week 13, your baby is the size of a peach, and its vocal cords start to develop. The baby’s eyes are fully formed, and it can sense light. By week 14, the baby’s teeth buds begin to form, and the baby starts to make facial expressions.
Week 15 to 16: Growth Spurt
Your baby is now the size of an avocado, and its body starts to fill out. The baby’s ears begin to stand out, and it can hear sounds outside the womb. The baby also starts to grow fine hair all over its body, called lanugo.
Week 17 to 18: Developing Reflexes
At this stage, your baby is the size of a turnip. It starts to develop reflexes like sucking and swallowing, and it can hiccup. The baby’s bones also begin to harden.
Week 19 to 20: Active Baby
By week 19, your baby is the size of a mango, and it’s starting to develop a more active personality. The baby’s senses continue to develop, and it can now perceive touch. By week 20, the baby can hear more complex sounds, and the mother can feel its movements more distinctly.
Week 21 to 22: Facial Expressions
Your baby is now the size of a papaya, and its facial expressions become more complex. The baby also starts to grow eyebrows and eyelashes. The digestive system becomes more developed, and the baby starts to swallow more.
Week 23 to 24: Survival Outside the Womb
At 23 weeks, the baby is about 11 inches long and weighs around 1 pound. The lungs continue to develop, and the baby begins to produce surfactant, a substance that helps the lungs expand and contract properly. The brain is growing rapidly, and the baby can now recognize familiar sounds, such as their mother’s voice.
At 24 weeks, the baby is approximately 12 inches long and weighs around 1.5 pounds. The lungs are continuing to mature, and the baby is beginning to practice breathing. At this stage, there is a possibility of survival outside the womb, although it is still considered very premature.
Week 25 to 26: Senses and Sleep
By week 25, the baby’s hearing is fully developed, and they can respond to noises outside the womb. The baby’s eyes are also beginning to open, and they are able to distinguish between light and dark. The baby now has regular periods of sleep and wakefulness, and their sleep patterns may begin to reflect those of their mother.
At 26 weeks, the baby weighs around 2 pounds and is approximately 14 inches long. The baby’s eyelashes and eyebrows are now fully formed, and they have a better sense of taste. The brain is continuing to develop, and the baby’s movements are becoming more coordinated.
Week 27 to 28: Lung Maturity
At 27 weeks, the baby is around 14.5 inches long and weighs approximately 2.2 pounds. The lungs are now capable of producing surfactant, and the baby is practicing breathing more frequently. The baby’s brain is developing rapidly, and they may be able to recognize familiar faces.
By week 28, the baby weighs around 2.5 pounds and is approximately 15 inches long. The eyes are now fully formed, and the baby has a better sense of depth perception. The lungs continue to mature, and the baby’s chance of survival outside the womb increases significantly.
Week 29 to 30: Rapid Brain Growth
At 29 weeks, the baby is around 15 inches long and weighs approximately 2.8 pounds. The brain is growing rapidly, and the baby’s movements are becoming more complex. The baby is now capable of hiccupping, which may be felt by the mother.
By week 30, the baby weighs around 3 pounds and is approximately 16 inches long. The brain is developing at a rapid pace, and the baby is now capable of processing information. The baby’s bones are becoming harder, and their movements may be more restricted due to the lack of space in the womb.
Week 31 to 32: Immune System Development
At 31 weeks, the baby is around 16 inches long and weighs approximately 3.3 pounds. The immune system is beginning to develop, and the baby is now capable of fighting off some infections. The baby’s movements may be more forceful, and the mother may feel some discomfort.
By week 32, the baby weighs around 4 pounds and is approximately 17 inches long. The baby’s skin is becoming smoother, and they are starting to accumulate more body fat. The brain is continuing to develop, and the baby’s movements may be more coordinated.
Week 33 to 34: Final Growth Spurt
At this point, your baby will continue to put on weight, adding approximately half a pound each week. The bones in their skull will remain soft and flexible, allowing for a smoother journey through the birth canal. Your baby’s lungs will also continue to mature, and they will practice breathing movements in preparation for life outside the womb.
Week 35 to 36: Preparing for Birth
As your baby’s organs are fully developed, their main focus will be on packing on more weight and practicing the skills they will need once they are born. Their hearing will be fully developed, and they will be able to recognize your voice and other familiar sounds. Your baby may also begin to settle into the head-down position in preparation for birth.
Week 37 to 40: Full-Term Pregnancy
At 37 weeks, your pregnancy is considered full term, which means your baby is fully developed and ready to be born at any time. However, most babies will wait until closer to 40 weeks before they are ready to enter the world. During this time, your baby will continue to gain weight and develop their immune system. Your cervix will begin to thin out and dilate in preparation for labor. As your due date approaches, you may experience Braxton Hicks contractions, which are practice contractions that help prepare your body for labor.
Conclusion
In conclusion, fetal development is a remarkable journey that lasts for nine months. Each week brings new changes and developments, from the formation of organs and limbs to the growth of hair and nails. Understanding the process of fetal development can help you feel more connected to your baby and appreciate the incredible journey they are on as they grow and prepare for life outside the womb.
