The experience of becoming pregnant is amazing and full of hope and anticipation. Understanding the developmental phases of your baby can make this time even more special as they grow and change every week. Understanding your body’s processes fosters a closer bond with your child and makes you feel more equipped for the upcoming months.
Every stage of development has new developmental milestones, starting from the first few weeks when your baby is just a tiny cluster of cells and ending in the final stages when they are ready to enter the world. Every moment matters, whether it is for the development of the heart, the emergence of tiny fingers, or the capacity for sound perception.
We’ll examine in more detail what occurs in each week of pregnancy in this article. You’ll have a better understanding of how your child is developing, changing, and getting ready for life outside the womb from conception to delivery.
The journey of fetal development during pregnancy is amazing; the baby’s growth and abilities change significantly every week. Parents can better connect with the life growing inside them by being aware of these stages, from the first heartbeat to the development of organs and senses. This article will walk you through each week’s major developmental milestones to help you better understand how your baby grows and what to anticipate when you’re pregnant.
- General information
- Development in the first trimester
- First
- Second
- Third
- Fourth
- Fifth
- Sixth
- Seventh
- The eighth
- Ninth
- Tenth
- Eleventh
- Twelfth
- Thirteenth
- Development in the second trimester
- Fourteenth
- Fifteenth
- Sixteenth
- Seventeenth
- Eighteenth
- Nineteenth
- Twentieth
- Twenty-first
- Twenty-second
- Twenty-third
- Twenty-fourth
- Twenty-fifth
- Twenty-sixth
- Twenty-seventh
- Video on the topic
- 1-4 weeks of pregnancy. Fetal development and changes in the mother
- Fetal development 10-14 weeks of pregnancy. 1 trimester screening.
- Fetal development by weeks of pregnancy. Fetal brain.
- FETAL DEVELOPMENT BY WEEKS OF PREGNANCY | The main stages of the formation of the child in the mother"s belly
General information
Pregnancy is a magical time, a woman is preparing to become a mother and does not even imagine the entire global scale of the processes that take place inside her body. From the moment of conception, when two reproductive cells merge – male and female, a lot is already predetermined. At this moment, the sex of the baby is determined (the fusion of chromosomes of the XX type guarantees the development of a girl, and XY – a boy). At this moment, it is absolutely certain who the baby will look like, what kind of eyes and hair, height, talents and abilities, what hereditary diseases the child may have. Only a woman does not know all this, nature knows this.
An average pregnancy lasts forty weeks. Obstetric weeks are defined as beginning on the first day of the last menstrual cycle in the cycle of conception, while embryonic weeks are the period of time during which the baby truly exists (from the moment of conception). The units of measurement used for all calculations made while waiting for the baby are obstetric weeks. Based on these terms, ultrasound specialists have created tables and will use them to evaluate the fetus’s growth and development, as well as its proper formation.
Only 5 percent of babies are born at precisely 40 weeks; the remaining babies are born between 38 and 42 weeks. A miscarriage occurs before 22 weeks, and a child born before 37 weeks (inclusive) is deemed premature.
Intrauterine development is divided into periods and stages. When the fertilized egg is just getting ready to implant itself into the wall of the uterus, it is called the preimplantation period. After implantation, the embryonic period begins, which lasts 8 weeks, from the 10th obstetric week the fetal period begins. In the embryonic period, all organs and systems are laid down, in the fetal period they only grow and increase in size. Factors influencing the development of the fetus are multifaceted: this includes the health of the woman, and the heredity of the parents, and bad habits (smoking, alcohol), and the state of the environment in the area of residence of the expectant mother, and her social status (nutrition, provision of vitamins), and the availability of medical care and much more.
Please be aware that the baby’s weekly development is shown in obstetric weeks.
Development in the first trimester
First
Not yet a baby. Not at all. The woman may not even be planning a pregnancy at this point, but she has started her period. The endometrium that proliferated during the previous menstrual cycle is currently being removed from the uterine cavity by the body. When the week comes to an end, the luteal phase starts, follicle-stimulating hormones are produced, and hormonal changes start.
Second
Hormones influence the maturation of follicules in the ovaries. One of them will rupture by the end of the week, releasing a fertilized egg into the left or right fallopian tube’s wide section. It has a day or so to live. It will come into contact with the sperm on these days.
When the cells combine during conception, their DNA starts to form a new, fully formed cell. It is one of a kind; there isn’t another one like it in the entire world. All the details regarding the future child are contained in it.
The fertilized egg gradually descends into the uterine cavity, propelled by the villi within the fallopian tubes. Progesterone is actively produced by the woman’s body. It develops and primes the reproductive organ’s inner layer for the attachment of the embryo. We now refer to the infant as a zygote. The zygote divides incessantly.
Third
3-6 days after ovulation, the zygote ceases to be one and becomes a blastocyst. It enters the uterine cavity and still floats freely in it, not being attached to the uterine wall. The blastocyst has two layers: the inner one will later become the child"s internal organs, and the outer one will have to show itself now – it is responsible for the implantation process. If the attachment process does not take place or goes wrong, the pregnancy will not develop. Around the 7-9th day, the blastocyst sticks to the wall of the uterus, but there is also a later implantation. The most important process lasts about 40 hours. After the blastocyst has “stuck”, it begins to gradually sink into the endometrium. The villi of the outer layer produce a special enzyme that dissolves the cells of the endometrium. The blastocyst actually “buries” itself in it.
The fertilized egg sinks into the endometrial layer, and the blastocyst’s outer layer villi attach to the woman’s blood vessels, allowing the embryo to start feeding and get all the nutrients it needs from the mother’s blood to grow.
Fourth
The woman has not yet started to have a delay, but the blastocyst baby has already become an embryo and has acquired its first characteristics: its weight is about 0.5 grams, its height is less than 1 millimeter. Three embryonic petals are formed. The outer layer will later become the baby"s skin, the middle layer will form the basis for the gradual formation of the heart and blood vessels, genitals, bones and muscle tissue, and the inner layer will be the organs of digestion, respiration and the genitourinary system. The rudiment of the spinal cord appears. All other organs exist in the same state of prototypes. They are still groups of cells similar in purpose, but in a few days internal organs will begin to form from them. The baby itself looks like a ball. At this stage, you can congratulate it on its first independent achievement: it has learned to extract oxygen from the mother"s blood with the help of the chorion.
Fifth
It"s time to please mom. It"s time to take a pregnancy test. A delay has begun, Some women can already feel the first signs of pregnancy, but this is not necessary. The embryo is doing better than ever – this week its heart will begin to beat. While it is two-chambered, the process of forming sections is still ongoing, but by the end of the 5th week it will begin to contract rhythmically. It is at the end of this week that you can see the baby"s heartbeat for the first time on an ultrasound, if it is performed with a vaginal sensor. Cell division and organ formation continue. The growth of the embryo this week is already 1.5-2 mm, weight – within 1 gram. Sex cells begin to be laid down.
As the baby is currently laying the neural tube, which will eventually develop into the brain and spinal cord, this week is regarded as one of the most significant. This process has many intricate steps.
Sixth
This week, a lot of people get ultrasounds to confirm their pregnancy test results. However, the embryo is still very small, so the doctor won’t see much just yet, aside from the fertilized egg in the uterus. But it’s grown almost twice as much as it did last week. It weighs about 1.5 grams and grows to a maximum length of 3–4 mm.
The development of the baby’s immune system starts at this point, as the thymus gland is established. The heart is starting to beat, albeit erratically. The formation of arms starts with the appearance of dark dots, or protrusions, where the eyes should be and small dimples where the ears should be. Although the baby is still immobile, it will only take him approximately a week to learn how to move.
Seventh
The baby has doubled its height again and is now about 6-7 millimeters. Weight – 2 grams. Now it can be assessed using a visual and beloved by pregnant women method – in comparison with fruits and vegetables. At the 7th obstetric week, the baby reaches the size of a white bean. At the current stage, nerve fibers are formed, this is a very important process. It depends on how the body of a tiny person will work. By the end of the 7th week, the baby gains the ability to move, but for now he moves reflexively, as new nerve fibers are formed. The formation of the organs of vision begins, therefore at the 7th week it is important for a woman to consume a sufficient amount of vitamin A and folic acid. The only intestine is divided into sections, they will later become the esophagus, stomach, pharynx. And the newly formed pancreas this week begins to produce the first insulin. Of the respiratory organs, there is only the trachea so far. The heart becomes four-chambered and completely takes over the pumping of blood throughout the entire body of the embryo. The gender is not yet obvious: both boys and girls have only genital tubercles of the same appearance where the genitals are to develop. The embryo does not yet look like a person at all, but the cluster of cells does not resemble one either, now it looks like an alien creature with widely spaced dark dots-eyes and a gigantic head in relation to the body. There are no fingers, there are fins at the end of the forelimbs. There is still a tail. The baby has learned to bend and unbend.
The main placenta emerges, with a maximum thickness of one centimeter. The uteroplacental blood flow starts to form.
The eighth
"Everything for the nervous system" is the week’s motto. The process that is most significant and important right now is its formation. And it moves along quite swiftly. The cerebellum is starting to emerge, and the brain and spinal cord have parted. The infant can move its head.
The woman may experience all the "delights" of early toxicosis after the placenta appears, as her sensations have already changed. You won’t need to wait long because the uncomfortable feelings should start to lessen toward the end of the first trimester and eventually go away completely. The baby is taller than 1.5 centimeters, which is a significant development. It is about the size of a small grape. Facial structures are still developing. The baby’s external genitalia start to form under the influence of the mother’s hormones, but the sex cannot yet be determined.
Ninth
The similarity between the embryo and a person is increasingly noticeable – all parts of the body have formed. The formation of organs is complete, growth begins. In a few days, the baby will no longer be called an embryo and will become a fetus. The baby"s head is pressed to the chest, but the tail has decreased, now it looks more and more like a human tailbone. The baby"s main achievement now is the ability to open and close his mouth, he has already learned this. The formation of future teeth inside the jaws begins. Along with the cerebellum, the pituitary gland appears in the brain. Cranial and spinal nerves are laid down. This gives the baby a new skill – the ability to clench and unclench fists.
The kidneys and thyroid gland start to function, the liver starts to function, and the first of its own lymphocytes emerge. The placenta starts to function at full capacity this week, which is the most important thing to note. Now, it acts as a barrier and provides protection in addition to "feeding" the infant. The infant is about the size of a large grape, standing 2 cm tall and weighing 3–5 grams. The ovum has a diameter of roughly 35 mm.
Tenth
The development of the embryo has ended and the fetal stage has begun. Until it is born, the infant is referred to as a fetus. It already has a human appearance on the outside; it has four limbs, a tailbone, and a head in addition to the absence of a tail.
The baby is between 2.3 and 3.8 cm tall and weighs roughly 10 grams. He is about the size of a small plum or a bead of reasonable size. The nervous system is still growing and splitting.
The brain has two hemispheres. The movements of the brain are not yet controlled, but everything is moving in this direction – the formation of the first neural connections begins. By the end of the week, the baby begins to bring his hands to his mouth, touch his face. Organogenesis is fully completed, now the organs only have to grow. The kidneys actively produce urine, the baby swallows water and urinates, the water is renewed every 3.5-4 hours. The head is rounded, but still remains very large in relation to the body. Lips and eyelids have appeared, the nose and ears are blocked. Now the baby has a neck, and he begins to turn his head. At the current stage, the baby can be congratulated on the fact that his first hair is starting to grow, thin skin begins to feel the first tactile sensations. Arms are longer than legs, there are small nails on the fingertips, joints (elbows and knees) work. From this week, the process of bone mineralization begins, so far they are more like cartilage. Also at this stage, the diaphragm appears. The baby is free in the uterus, he floats and constantly turns over. At the end of the 10th week, the baby begins to distinguish (so far only conditionally) taste – taste buds are formed on the tongue.
Eleventh
The dangerous period has almost passed. The internal organs "rehearse" interaction. The baby"s growth slows down somewhat with the end of the embryonic period, but the weight gain with each subsequent week will be more and more significant. The baby weighs more than 15 grams, his height is 5-7 centimeters. In size, he resembles an average pear. Already now, if the baby is ahead of the fetometry norms, there is reason to assume a tendency towards a large fetus. The anatomy of the fetus is perfect, there is everything, but only very small and functionally immature. At this stage, the baby will have to master one of the first reflexes – grasping. Now he has become more cheerful, he can grab the umbilical cord, his own legs. The head visually decreases slightly. If earlier it made up two thirds of the total body volume, now it is only half. The eyes have almost completed the journey from the lateral surfaces of the head (like a fish) to the center of the face and at this stage occupy almost the correct anatomical place. The formation of the retina, iris, lens and cornea is actively underway. Bones begin to accumulate calcium, the pregnant woman"s diet should be composed taking into account the increased need for it.
This week, you can congratulate the infant on learning how to use his legs to push off the obstacle. The baby pushes off and swims in the opposite direction if he reaches the uterine wall. The woman does not feel these pushes, though, because they are still very light. The baby has acquired the ability to yawn, which is another reason to celebrate.
Twelfth
Your baby is with you for exactly 10 weeks (idea for a family holiday dinner!). His height reaches 7-10 centimeters, and his weight is about 20 grams. These parameters are comparable to a medium-sized lemon. The body is still disproportionate – the head is large, and the legs remain shorter than the arms. But the eyesare completely in their proper place, which immediately gave the child a completely human appearance. The formation of the eyelids is complete, but the baby cannot open his eyes yet. The auricles are growing, and this week the lobes appear. The nose also begins to grow actively. Now even on a blurry ultrasound image of poor quality, the relief of the face is visible, and those with large noses already differ in appearance from their snub-nosed peers. The spinal cord, which was "in charge" of nerve impulses, begins to transfer authority to the brain.
The infant is skilled at using its sucking reflex. He already enjoys amniotic fluid after his mother ate chocolate considerably more than after eating garlic, demonstrating his flawless ability to discriminate between flavors.
The intestines, the formation of which is complete, begin to master the first muscle contractions that will become peristalsis. This week, boys get a penis, and girls get labia, but the organs are still small, and it is not always possible to see the baby"s sex on an ultrasound. To avoid confusion, it is better to ask the doctor this question later. Periods of sleep are replaced by periods of activity, muscles grow, and therefore the baby moves actively (even in his sleep), he already knows how to suck his finger. Facial movements appear – he folds his lips into a tube and wrinkles. From this week, the baby begins to empathize with his mother: if she is worried, his heartbeat quickens, if she is calm, the baby is also calm. Experts cannot explain this connection, but there is an assumption that stress hormones are to blame.
Thirteenth
The baby gains weight almost daily. Now in size he resembles a solid onion, his height is about 12 centimeters, weight is about 30-35 grams. The baby makes a depressing impression – he is very thin, covered in wrinkles, like an old man and all bright red. And all because he does not yet have subcutaneous fat, and all the blood vessels are visible through the thinnest skin. The head is in no hurry to acquire normal proportions and still remains large. The arms are longer than the legs, but the legs also begin to grow actively from this week, and soon the disproportion will be eliminated. The length of the femur this week is on average 8.5 mm. The formation of the middle ear is complete, but the process continues in the outer and inner ear, due to which the baby begins to hear, but so far only perceives sound as a vibration of waves. By the way, all reptiles hear this way. This will continue for about two more months, until the mature structures of the brain allow sounds to be transformed into normal and familiar to our ear.
The brain matter is actively growing in the brain, every day it becomes 250 thousand new cells more. The baby has learned to shudder, hug his shoulders. In girls, the ovaries fall into the basin, and now there are about two million eggs in them. This is a personal record for each lady, since then the number of oocytes will gradually decrease. The ovarial reserve is limited. Little boys still cannot boast of the omission of the gonads into the scrotum, this will happen before childbirth, but at this time they form the prostate gland. Bone mineralization is in full swing: the first to harden the skull and spine and only then – limbs. This week the baby gets the ribs. All organs of the respiratory system are formed, and the chest begins to expand. Voice ligaments are formed.
Development in the second trimester
Fourteenth
The baby is currently growing to be 12–14 centimeters in length and 40–50 grams in weight. It’s about the size of a small grenade. The process of gaining weight will start later, even though the tiny organism devotes all of its internal resources to the growth of its nervous system, bones, and muscles. Although most babies have a respectable-sized head of hair, all of them are natural blondes because the pigment needed to color the hair has not yet developed.
The baby should feel proud of himself for having fingerprints at this point in the intrauterine path. The design on the pads is exclusive to him and cannot be found anywhere else in the world. The infant’s eyes start to discriminate between light and dark; they are not yet able to do anything more. The baby moves more actively when exposed to intense light that is focused directly on the stomach.
The spinal cord produces blood cells while giving up its control over nerve impulse regulation. The brain is developed enough to take command of systems and organs. Up to 25 liters of blood can be pumped by the baby’s heart every day. The baby discovered how to smile this week, instinctively if not consciously. Similarly, when he is still a newborn, he will smile brilliantly without having any teeth.
Fifteenth
The baby is getting bigger. Its size is comparable to an apple – its height is 14-16 centimeters, and its weight is about 75 grams. The baby"s skin is covered with thick vernix caseosa, which performs protective functions. To prevent it from being washed away by amniotic fluid, it is held in place by lanugo – thin colorless hairs on the skin. The first convolutions appear in the brain, and the baby is noticeably "smarter". The cerebellum already better coordinates the movements of the limbs. Dark green original feces, which is called meconium, begin to be deposited in the intestines, this is what the baby will empty itself with in the first days after birth.
While girls do not yet produce their own sex hormones and are happy with their mother’s, boys start to produce their own testosterone. It is normal for the volume of amniotic fluid to increase.
Sixteenth
Gradually, the baby gains weight, and now weighs up to 115 grams. The baby"s height is 16-17 centimeters, in size, it resembles a large avocado and could easily fit in the palm of an adult. The neck has completed its formation, now the fetus has acquired the ability to hold its head straight, and not pressed to the chest. The muscles responsible for eye movements have begun to work. Under the eyelids, the baby begins to quickly move its eyeballs in its sleep. Eyelashes have appeared. The forehead begins to protrude forward, which makes the baby look more and more like a little person. The formation of the muscular frame has been completed, now all the muscles are only growing. The facial muscles are better developed than others – the baby knows several dozen different grimaces. The child begins to distinguish high-frequency vibrations of sounds: the sound of a doorbell from an alarm clock, dad"s voice from mom"s. This week, the endocrine glands begin to function fully. The length of the umbilical cord reaches half a meter.
This week, you can congratulate the baby on beginning to make his own hemoglobin and his parents on being able to accurately determine the baby’s gender through ultrasound. And here’s another oddity from this time period: the baby was discovered to spit and hiccup.
Seventeenth
This week is notable for the fact that the size of the baby for the first time exceed the size of the placenta – the baby weighs about 160 grams, and its growth reaches 17-19 centimeters. In size, he looks like a newborn puppy. Subcutaneous fat begins to be produced this week, now the baby’s weight gain will be more intense, along with this, thinness will disappear and pretty roundness will appear. The kid is already similar to one of the parents, he has all facial features formed. The outer ear is formed, but subtle and delicate processes in the internal. The world of sounds for the baby becomes more diverse: the first transformation of sound waves begins, in connection with which the baby begins not at the level of high -frequency vibration, but almost like you and I, perceive the loud sounds and the knock of my mother’s heart. It is believed that this week the baby begins to see dreams. The nervous system is so developed that the baby has acquired the ability to coordinate simple and combined movements. This means that he can suck his fist not because it happened, but because he wants to. The instinct of self-preservation appears – when a loud sound occurs, the baby groups, contracts. Now the baby sleeps less. Periods of wakefulness are filled with learning about the world – he feels himself and the space around him.
Eighteenth
The baby now weighs up to 240 grams, his height is about 22 centimeters. In comparison with vegetables and fruits, the child is comparable to a ripe mango. This week, the growth of the head slows down, while all other parts of the body do not slow down. This is important so that there is no disproportion. The cerebral cortex is formed very intensively. The process of mineralization of the bones of the skull and large paired bones is completed. For the first time in its entire intrauterine history, the baby"s legs exceeded the length of its arms. The baby swallows up to 400 ml of amniotic fluid per day. This is how he trains his digestive system and urinary organs.
Nineteenth
Now the baby will not grow as fast as before. But he will gain weight every day. Now his height is 22-25 centimeters, and his weight is about 300 grams. He resembles a large tomato. The skin begins to smooth out, but so far the changes are minimal – not much subcutaneous fat has formed. First of all, it is deposited in the neck, on the shoulder blades and on the lower back. Eyebrows and eyelashes are formed. The baby has been moving for a long time, but it is now that he has reached the size at which a woman can begin to feel him. Multiparous women, at least at the current stage, almost always feel when the baby begins to push. This week, the baby can be congratulated on gaining full hearing. Now he begins to perceive sound waves, like you and I, but he hears mainly what is happening inside the mother – how her heart knocks, the intestines are working. Only the mother"s voice and loud sounds from outside reach through the strong abdominal wall and the layer of amniotic fluid.
You can begin to read your baby fairy tales and sing him songs; these will be felt as familiar to him from the moment of his birth and will help to soothe him.
Twentieth
Half of a pregnancy has now passed during this phase. The infant’s development has advanced significantly. At present, his dimensions resemble those of a papaya: height of 24–26 centimeters and weight of 360 grams. Though his cheeks have already shown through, his arms and legs are still slender and he is not as handsome as he was a few weeks ago. This week, the skin develops four layers.
The baby starts trying to open his eyes for the first time this week. The reflex of blinking is developed. The immune system starts to function at its peak during this time.
Whether the child is left- or right-handed now becomes clear. Right thumb sucking occurs in seven out of ten babies, and the dominant side is the thumb. Most women who are expecting their first child start to feel a slight, imperceptible push from within this week.
Twenty-first
The baby is getting prettier. Its weight is already more than 400 grams, and its height can reach 24-28 centimeters. In terms of size, it can be compared to a doll. The baby"s skin is no longer bright red and purple. The first layer of subcutaneous fat, although it is still thin, transforms the appearance of the baby. The formation of fat plays a huge role in the survival of the child, it helps to maintain internal heat. Heat loss due to a small amount of subcutaneous fat is one of the main causes of death in premature babies. The head now accounts for about a quarter of the body proportions. By the time of birth, the head will make up only a fifth of the total volume of the baby"s body. A tummy has appeared. The baby increasingly resembles a newborn. The nervous system develops without breaks or days off, thousands of new neuron cells appear every second. The brain actively forms grooves and convolutions. Reflexes develop and are honed. A center develops in the brain that will later be responsible for recognizing speech and the native language.
This week, you can give the baby congrats for understanding the difference between day and night and for having something approaching a routine. Though it might not be exactly the same as his mother’s, their routines will eventually start to align.
Twenty-second
Childbirth that occurs this week (this also happens) is no longer considered a miscarriage. They are classified as premature births. And the baby has a chance of survival outside the mother"s womb. The baby"s weight is more than 500 grams, height is 30 centimeters. The size is comparable to a corn cob. The baby already looks like a newborn. Fatty tissue this week begins to spread throughout the body, the formation of the spine is completed. The maturation of the lungs begins. The baby"s worldview is not limited to what is happening in the womb. He becomes more emotional: he responds with calm to stroking and his mother"s quiet voice, he worries and gets nervous if he hears too loud sounds on the other side of the abdominal wall.
Twenty-third
The baby"s growth remains almost the same, it has slowed down – a little more than 30 centimeters. Weight increases – now the fetus weighs an average of 550-600 grams. Heredity factors begin to affect growth and weight (small parents – a small child, tall parents – a large baby). There are fewer and fewer folds and wrinkles on the baby"s skin. There are none at all on the face. The least amount of subcutaneous fat is on the ribs, the arches of which are clearly visible through the skin. The grasping reflex becomes local, that is, the baby can deliberately grab something with his hand. A respiratory reflex is formed – the lungs make special reflex movements. Later, this reflex will come in handy when the baby begins to breathe air.
Sebaceous glands and perspiration are functioning. The youngster already has sounds that they like and dislike.
Twenty-fourth
Babies start to kick more forcefully, and pregnant women are no longer suspicious of this pushing. When individual characteristics are taken into consideration, the height and weight indicators of babies start to diverge significantly, making it more challenging to compare them to the average. And this is standard practice: 31 centimeters in height and 650–700 grams in weight. The baby starts to progressively shed the lanugo hair on their body this week. By the time of birth, this process of falling out should be finished. In the first few weeks of the newborn’s life, if there is any remaining lanugo, the hair will fall out naturally. There are tendon reflexes.
Twenty-fifth
A qualitatively new period begins – the baby will have to start learning to survive, because the environment outside the mother"s belly is very different from the intrauterine one. The baby"s height is about 33 centimeters, weight is about 750-800 grams. The baby no longer looks like a wrinkled dried fruit, the skin has almost smoothed out. Melanin production has begun, due to which the skin becomes pinkish. The auricles remain soft, the degree of maturity of the lungs is low. If the baby is born, it will be severely premature, but it has a chance of survival. A special substance, surfactant, begins to be produced in the lungs. It will help the alveoli not to stick together during independent breathing.
The WHO considers the fetus to be viable. The average estimate for survival is between 15 and 17 percent. The baby sleeps in waves, with REM sleep lasting longer than NREM sleep.
Twenty-sixth
The baby"s weight is from 850 to 900 grams, height is 33.5 cm. The baby"s auricles are still soft and slightly protruding, as the cartilaginous tissue hardens, they will take a normal position. The amount of cheesy grease on the baby"s body and face decreases. Receptors that will be responsible for the sense of smell are being formed. The fetus sleeps up to 23 hours a day, that is, almost constantly. The brain establishes a connection with the adrenal cortex, the child develops its own hormonal background. The pituitary gland begins to produce growth hormones. In most boys, this week the testicles descend from the abdominal cavity into the scrotum. The viability of children born at this time increases to 30-35%, although the degree of maturity of the lungs is still insufficient.
Twenty-seventh
The infant weighs between 950 and 1000 grams and reaches a height of 36 centimeters. The baby starts to assume the so-called flexion pose when it can no longer fit inside the uterus at its maximum height. Since the child’s genitalia are covered, it is now challenging to ascertain the child’s sex if this hasn’t been done previously. As the baby’s vision gets better, it can now discriminate between light and dark as well as different-intensity color-defocused spots. The accumulation of surfactant in the lung tissue continues. The survival rate rises sharply, with up to 75% of newborns born at 27 weeks surviving.
Week | Fetal Development |
1-4 | Cells begin to divide and form the embryo, and the placenta starts to develop. |
5-8 | The heart starts beating, and arms and legs start to form. The baby is about the size of a pea. |
9-12 | Fingers and toes are developing, and the baby"s organs begin functioning. Facial features become clearer. |
13-16 | The baby can start making movements, although you may not feel them yet. Bones are hardening. |
17-20 | You may feel the baby move. The baby is growing rapidly and developing more muscle. |
21-24 | The baby can hear sounds from outside the womb and may respond to them. Lungs continue to develop. |
25-28 | The baby opens their eyes and can blink. Brain activity increases, and the baby starts to practice breathing. |
29-32 | The baby gains more weight, and the skin becomes smoother. Movements become stronger and more noticeable. |
33-36 | The baby is almost fully developed, and the lungs are preparing for breathing outside the womb. |
37-40 | The baby is now full-term and ready for birth. The organs are fully functional. |
Your baby grows and changes every week during pregnancy, making it an amazing journey. Gaining an understanding of the developmental process can increase your sense of awareness of your body’s internal processes.
Every stage of development, from the first moments of cell formation to the last moments before birth, represents a step toward the welcoming of a new life. Navigating the ups and downs of pregnancy can also be made easier by keeping up with current events.
As you progress through these thrilling months, don’t forget to look after yourself and cherish every milestone. Your baby is developing quickly, and each week they get closer to being in your arms.