Copyright ⓒ 2014 John Sangwon Lee, MD., FAAP
Fetus growth and development during the second trimester of pregnancy 임신 제2 삼개월기 태아의 성장 발육
- The period from the first day of the fourth month to the end of the sixth month is called the second trimester, the second trimester, or the second trimester.
- During the second trimester, morning sickness during the first trimester almost disappears, and morning sickness no longer occurs.
- Most pregnant women usually feel better and more emotionally stable than before their second trimester. Until the 8th week of pregnancy, the baby in the womb was called the fetus (Embryio), but from now on, the baby is called the fetus.
- Pregnant women can sometimes feel the fetus move little by little in the belly.
- The belly of the pregnant woman is so full that other people can see and recognize that she is pregnant.
- During this pregnancy, the fetus grows really fast day by day. Now, the male and female external genitalia are well developed so that the sex of the fetus can be easily discerned with the naked eye.
- During this period, especially, pregnant women should consume enough balanced foods that are evenly rich in nutrients.
- The sound of the fetal heartbeat can be heard with a stethoscope.
Growth and development of a 12-week-old fetus
6 months pregnant
Source-Pregnancy in Anatomical Illustrations, Carnation Healthcare Services, Los Angeles, CA From pregnancy to babysitting (Cheongmungak)
- A 12-week-old fetus is equivalent to a 14-week-old fetus.
- This is because, as explained before, the number of weeks of pregnancy is calculated from two weeks before the date of fertilization.
- For example, to say that you are 10 weeks pregnant means that you are 10 weeks from the first day of menstruation you had just before you became pregnant.
- “The term “a 12-week-old fetus” is equivalent to saying that it is 12 weeks from the date of fertilization when an egg and sperm meet.
- The weight of the 12-week-old fetus is 25 gm and the height is 8.0-9.3 cm.
- It is difficult for a 12-week-old fetus to survive birth. The skin has a lot of wrinkles, and the skin is pink.
- The subcutaneous fat layer of babies born at this time is much thinner than the subcutaneous fat layer of normal newborns born at term.
- Now, the placenta plays an important function in maintaining the baby’s growth and development. Estrogen, progesterone, human corionic gonadotropin, etc. are secreted from the placenta, and various nutrients and oxygen are supplied to the fetus through the umbilical vessels in the placenta.
- The central nervous system of the fetus becomes more active, and the limbs, fingers, ankles, knees, elbows, knuckles and toes can be bent and unfolded.
- The eyelids continue to develop further, and the hair on the head and the toenails of the nails continue to grow and lengthen.
- They also breathe through their lungs. The fetus can suck their fingers and play with more exercise than before.
- Because the fetus’s weight gain is significantly faster and the pregnant woman can gain a lot of weight, it can cause more discomfort because the pregnant woman is more strained in the lower back and back.
- During this period, the pregnant woman can easily lose its balance and fall easily. Walking or standing for long periods of time can easily get tired. At this time, you should wear shoes with low heels.
13-week-old fetus growth and development
- As in the previous week of pregnancy, the fetus grows and develops rapidly.
- The weight is about 50g and the height is 10.4~11.4cm (measured from head to hip). The ossicles form in the middle ear.
- A hearing center is formed in the brain, and the fetus can hear the mother’s voice and even the sound of the mother’s heartbeat.
- Eyebrows and stomach hairs continue to grow. The conjunctival corneal retina is formed more prominently.
- The skin layer is thin and transparent like a sheet of paper. The blood vessels in the subcutaneous layer, such as the head, arms, hands and chest, can be seen with the naked eye.
- Ribs in the rib cage can also be seen through the skin layer. The fetus also sucks hands.
14-week-old fetus growth and development
- The bones become calcified and hard, the limbs have more strength, and the joints in the limbs can be opened and closed.
- Depending on the function of the central nervous system, the water level muscles in each part of the body can move.
- In the narrow space of the uterus, the fetus is round, performs tricks, kicks, boxing, and does all kinds of exercise. Some early mothers are not easily aware of these baby movements in the womb.
- At 14 weeks of gestation, the baby weighs 80g, and the length from head to hip is about 10.8~11.6cm.
15-week-old fetus growth and development
- The skin, hair, eyebrows, eyelashes, nails, and toenails keep growing, and the heart keeps beating.
- As the eyes are still tightly closed and the baby grows rapidly, more fat tissue accumulates in the subcutaneous layer and begins to gain weight.
- The difference between the size of the head and the body is smaller than before. The fetus can do breathing exercises, go up and down as soon as the chest breathes, drink amniotic fluid into the airways, spit out the mouth, and be surprised to hear the sound from the outside of the pregnant woman.
- The weight at this time is 100g, and the length from head to hip is about 11.0~12cm.
16-week-old fetus growth and development
- At this time, you can move your toes and fingers well.
- You can do your whole body workout better than before.
- You can turn your torso to one side, do acrovec exercise, boxing, kick, and move your torso from side to side.
- The pads are formed more clearly on the limbs, and the shape of the finger pads is formed so that it can be taken into account. The eyes still cannot open, but the muscles in the eyes begin to move.
- Meconium can be pressed.
- The prostate begins to develop in the male fetus. The weight at this time is 150g, and the length from head to hip is about 12.5~14cm.
17-week-old fetus growth and development
- The fetal skin is secreted from the fetus’s skin, and the fetus’s skin is warmed with the fetus.
- Gastrointestinal fluid is secreted in the gastrointestinal tract, and the kidneys work to filter amniotic fluid.
- During this period, the fetus grows rapidly. The weight at this time is 200g, and the length from head to hip is about 13~15cm.
18-week-old fetus growth and development
- The 18-week-old fetus grows rapidly every day, and the sense organs such as tactile, taste, smell, hearing, sight are well developed.
- Memory and thinking skills can be improved.
- There are more than 5 million immature eggs in the ovaries of the female fetus. The nervous and musculoskeletal systems are more developed than before, allowing you to exercise in harmony.
- The weight at this time is 255g, and the length from head to hip is about 14~16cm.
19 weeks fetal growth and development
- The sensory organs of the 19-week fetus are more developed.
- In the womb, you can hear the voice of the mother’s breath, the sound of the heart.
- You can hear music or noise outside the mother’s body.
- From now on, your baby can respond to stimuli from the outside.
- Meanwhile, the amniotic fluid produced in the placenta is produced by the kidneys, and the kidneys secrete a very small amount of urine.
- The amniotic fluid drank goes into the stomach, and the amniotic fluid is absorbed into the blood in the stomach.
- Looking at it, I think I’m practicing eating.
- He moves his limbs well, sucks his fingers, and puts his hands on his face.
- The growth and development of the fetus can be surprising if you see the process of the fetus growing in the womb through an ultra-sound test.
- The weight at this time is 300g, and the length from head to hip is about 15~17cm.
20-week-old fetus growth and development
- The testicles of the male fetus produce sperm, and the testicles in the pelvic cavity begin to descend into the scrotum.
- Through the transparent skin layer, blood vessels under the skin can be seen with the naked eye, sweat glands are formed in the skin, the number of parenchymal cells increases with acceleration, and brain functions become more active.
- The weight at this time is 350g, and the length from head to hip is about 19cm.
21 weeks fetal growth and development
- The baby’s skin layer is still transparent, allowing the naked eye to see the blood vessels and ribs under the skin.
- The ossicles in the middle ear and bones in the inner ear are well formed.
- The fetus is able to distinguish between sounds made inside the mother and outside the mother. It is said that you can hear the sound of your stomach, the sound of your heartbeat, and even the sound of your mother tickling.
- It is said that when a 21-week-old fetus is born, the high and low tones of the mother’s voice, and pleasant and unpleasant sounds can be heard in a discernible manner.
- For these and other reasons, mothers and fathers say a lot of lovely words to a newborn baby, love them with a good glance, and love them a lot through physical contact.
- Studies have shown that the dad’s low-pitched voice is heard better than the mother’s high-pitched voice.
- When she gently touches and scratches the belly of her pregnant woman and tells her that she loves her, the baby is said to like it while kicking with her feet.
- The weight at this time is about 455g, and the length from head to hip is about 22cm.
- There is a saying from pregnancy to prenatal school. There are many guidelines that say, “Become prenatal like this.” In conclusion, this chapter is also a good prenatal guidebook.
- I think the best prenatal is for married couples to have a baby according to the information described in “Pregnancy, Delivery, and Childbirth” by planning the desired pregnancy at the right time for their lifestyle.
Growth and development of a 22-week-old fetus
- The 22-week-old fetus breathes in the amniotic fluid through the mouth and into the airways and exhales the amniotic fluid in the womb. Blood vessels and alveoli are formed in the lungs.
- So, in the future, it can function as the lungs by absorbing oxygen in the air through the alveoli and releasing carbon dioxide generated in the body through the alveoli.
- When a 22-week-old fetus is born, the probability of survival is 25% if the baby is well protected and nurtured in the neonatal intensive care unit.
- The skin layer is still thin and transparent and is covered a lot with sebum.
- White blood cells form in the bone marrow, which can fight bacteria and prevent infectious diseases.
- The weight at this time is 540g, and the length from head to hip is about 23cm.
Growth and development of a 23-week-old fetus
- Two nostrils are pierced in the nose and you can breathe through them.
- The number of alveoli and blood vessels in the lungs is increased, more vigorous and more developed, and the sprouts of permanent teeth appear under the 20 teething buds already formed in both jawbones.
- The sense of smell continues to be developed so that you can smell the mother’s milk, and the sense of touch around the mouth and lips is particularly well developed. If there is a nipple around the mouth and lips, it detects that it is a nipple and opens the mouth to put the nipple in the mouth and sucks it, so the contact nerve is well developed in that area.
- The string contains one vein and two arteries.
- Both blood vessels are wrapped in jelly-like colloids.
- Through this umbilical cord, the fetus grows by ingesting nutrients and oxygen from the mother.
- There are 33 vertebrae in total, 150 joints in the body, and 1000 tendons.
- I am grateful for the hard work of the scientists who count these numbers one by one. I often think that there are so many people in the world who really won the Nobel Prize.
- The weight at this time is 700g, and the length from head to hip is about 23.5cm.
Growth and development of a 24-week-old fetus
- The alveoli become more developed and can inhale amniotic fluid and some can be expelled through the airways.
- The spinal column grows, develops, and becomes stronger to support the head and torso.
- The body also moves in response to sounds heard outside of the mother’s body. And it can react according to the high and low tone and tone of the music, and when the pregnant woman’s belly touches, the baby can feel it. If you listen carefully to the belly of the pregnant woman, you can hear the sound of the fetus’s heartbeat.
- The weight at this time is 910g, and the length from head to hip is about 24cm.
25-week-old fetus growth and development
- More fat tissue accumulates under the baby’s skin, making the baby plump.
- The fetal ultrasound test reveals a fetus sucking a finger. Cerebral, lung, muscle, and tongue functions are more developed and active.
- You can open your eyes and detect the contrast of light.
- Research suggests that the baby’s reaction can be handled by the intensity of light and shade on the pregnant woman’s abdomen.
- Eyelashes can grow a lot.
- The weight at this time is 1kg, and the length from head to hip is about 24.5cm.
26-week-old fetus growth and development
- The baby grows and develops at maximum speed, the lungs function better, and the sound of the mother’s speech, the sensation of touching the belly, etc.
- can be sensed. In the case of a male fetus, the testicles gradually descend from the pelvis into the scrotum, and the female fetus’s labia are still small and the clitoris is covered by the labia.
- The weight at this time is 1.1kg, and the length from head to hip is about 25cm. From the next week, the third trimester of pregnancy (the third trimester) begins.
27-week-old fetus growth and development
- The baby gains weight and grows, becoming plump and occupies most of the womb. As before, you can’t actively do various exercises,
- but you can do kicking or stretching exercises in the womb.
- The functions of important organs such as the brain, heart, kidneys, and stomach become more active.
- The eyeball can move in orbit, and depending on the function of the nervous system, breathing, body temperature control, heart rate, and gastrointestinal movements can be controlled.
- It is said that sensory functions such as olfactory, taste, tactile vision, etc. are more developed, and it is possible to distinguish between sunlight and artificial rays.
- The weight at this time is 1.25kg, and the length from head to hip is about 26cm. Copyright ⓒ 2014 John Sangwon Lee, MD., FAAPTwo
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“The information contained in this publication should not be used as a substitute for the medical care and advice of your doctor. There may be variations in treatment that your doctor may recommend based on individual facts and circumstances.
“Parental education is the best medicine.“