All her vital life systems are now working independently and the umbilical cord can be cut. The placenta is now redundant and in the third stage of labor, it detaches from the uterine wall and follows the baby out through the vagina. After growing painstakingly inside her womb for nine months, the baby finally comes face to face with her mother. The sweet smile seen inside the womb is gone now, as the baby is thrust into a noisy, bright world and starts to feel uncomfortable sensations like cold and hunger. Her smile won't be seen again until she is at least 4 weeks old. Each year around the world, about 130 million women go through the complex cycle of pregnancy and birth. Our increasingly sophisticated understanding of the process has drastically reduced the risks for both mother and baby.
And now for this little girl, after 9 months in the womb and a healthy delivery, she's on her own. Her parents will feed her and keep her warm, but for the first time, her body must keep itself alive. She's gone from egg to embryo, to fetus, to trillions of cells of newborn baby. Her birth marks the beginning of her journey in the world, but she's already traveled an incredible path during her nine-month odyssey in the womb. Protected by her mother and following her own unique genetic blueprint, she's grown a face, arms, eyes and legs. She has a brain and nervous system to control her body, stomach and intestines to digest food and a heart to pump blood. She has learned to breathe, to hear, to feed, to remember and to tell her parents when she's hungry, tired, happy or in pain or before being born, and now she's ready to face the world.
Sunday, November 23, 2008
DC 2007-05-09, In The Womb 子宫日记 17
It's the final act and the countdown is on. Although it's impossible to tell exactly when the baby will be born, only 5 % of babies are born on their due date, the rest can emerge any time within two weeks of their expected arrival. The mother's kept guessing and waiting for signs, the first contraction of the uterus or the breaking water as the amniotic sac ruptures.
Nobody knows exactly what initiates labor, but it's the baby's lungs together with the placenta that determine the timing. When the lungs are mature, they secrete a protein into the amniotic fluid, which alters the placenta's production of hormones. It slows the release of progesterone and triggers the release of a new hormone, oxytocin, which initiates the contractions of the uterine wall. Oxytocin also inhibits memory and may play a role in helping women to forget the pain of birth and bond with their new babies.
During the first stage of labor, the baby's head is locked in the bottom of the uterus and is bearing down on the cervix, the barrier between the uterus and the vagina. The last thing to pass through the cervix was a tiny sperm 38 weeks ago. Now the cervix must stretch ten centimeters wide to allow the baby's head, her largest part to pass through.
For the mother, the pain of birth can be eased if she delivers standing up, sitting or squatting rather than lying on her back. This can also speed up the first stage of labor and reduce the likelihood of needing medical intervention or a cesarean. Labor's also painful and stressful for the baby, the squashing of the umbilical cord can easily constrict the supply of oxygen. To help the baby cope, her body releases large quantities of adrenalin to keep her heart pumping fast enough. Adrenalin also helps prepare the lungs for the lifetime of work they're about to begin.
Once the cervix has fully opened, the second stage of labor, the actual delivery begins. With each contraction of the uterus, the baby is pushed further through the cervix and vagina until eventually her head is just visible. (Baby's head is just coming here.) The contractions are only minutes apart now and after each one the midwife encourages the mother to push down hard and helps squeeze the baby out. (Breathe now, breathe, breathe. Here's your baby, the baby's head, checking the cord down. Yes, its contractions help this baby out, ok? Here you are. Hello. Honey, it's our typical baby.) As soon as the baby is delivered, her lungs drain off fluid and air rushes in, expanding the air sacs that in an instant begin extracting oxygen to keep the baby alive.
Nobody knows exactly what initiates labor, but it's the baby's lungs together with the placenta that determine the timing. When the lungs are mature, they secrete a protein into the amniotic fluid, which alters the placenta's production of hormones. It slows the release of progesterone and triggers the release of a new hormone, oxytocin, which initiates the contractions of the uterine wall. Oxytocin also inhibits memory and may play a role in helping women to forget the pain of birth and bond with their new babies.
During the first stage of labor, the baby's head is locked in the bottom of the uterus and is bearing down on the cervix, the barrier between the uterus and the vagina. The last thing to pass through the cervix was a tiny sperm 38 weeks ago. Now the cervix must stretch ten centimeters wide to allow the baby's head, her largest part to pass through.
For the mother, the pain of birth can be eased if she delivers standing up, sitting or squatting rather than lying on her back. This can also speed up the first stage of labor and reduce the likelihood of needing medical intervention or a cesarean. Labor's also painful and stressful for the baby, the squashing of the umbilical cord can easily constrict the supply of oxygen. To help the baby cope, her body releases large quantities of adrenalin to keep her heart pumping fast enough. Adrenalin also helps prepare the lungs for the lifetime of work they're about to begin.
Once the cervix has fully opened, the second stage of labor, the actual delivery begins. With each contraction of the uterus, the baby is pushed further through the cervix and vagina until eventually her head is just visible. (Baby's head is just coming here.) The contractions are only minutes apart now and after each one the midwife encourages the mother to push down hard and helps squeeze the baby out. (Breathe now, breathe, breathe. Here's your baby, the baby's head, checking the cord down. Yes, its contractions help this baby out, ok? Here you are. Hello. Honey, it's our typical baby.) As soon as the baby is delivered, her lungs drain off fluid and air rushes in, expanding the air sacs that in an instant begin extracting oxygen to keep the baby alive.
DC 2007-05-07, In The Womb 子宫日记 16
She is likely to be turned head down in the womb, getting ready for birth. For the mother, this change could be marked by some painful kicks straight to her ribs. The type of music a baby is exposed to can alter her mood. Fast music stimulates and excites her. Music that is closest to the natural sounds and rhythms of the human voice, such as classical or choral music, has a sedating calming effect. If she hears the same music over and over again, she may even be able to remember it. At 33 weeks just over 8 months, the fetus may recognize a particular piece of music and even jump in time to it.
Some scientists argue that there is very little difference between the brain of a newborn baby and that of a 33-week-old fetus. Well, once it seemed that the mental development of a baby began at birth. Now it appears that birth could be a relatively insignificant event in developmental terms. She may have to support herself after birth, but as for the process of thinking, learning and remembering she has already been hard at it for 3 months, and her brain will continue to grow at the same rate for the next year.
The final phase of pregnancy is a demanding one for the mother. Many women feel uncomfortable during the last couple of months. The weight of the baby together with pressure on the spine and the battle for space can all cause her back and legs to ache. She may be feeling anxious about the birth and is likely to be short of breath as her lungs struggle to absorb 20 percent more oxygen than normal.
One of the many things revealed by the 4-D scans is the fact that babies have rapid-eye-movement sleep. This is a period of sleep when the eyes flicker around behind the eyelids. Later in life, this is an indication of dreaming. This gentle flicker of an eye could be a sign that the fetus, still with a month to go before being born, is already dreaming. There was so little life experience. It's hard to imagine what she's dreaming about, perhaps playing with her feet or maybe the gurgling of her mother's stomach.
In just over 8 months, the brain has grown approximately 100 billion neurons with 100 trillion connections. The brain and head have grown as big as they can in the womb, yet they are still small enough to squeeze through the mother's pelvis. The fetus can survive if born any time from about 35 weeks without much medical help. Although the longer she stays inside, the healthier she will be at birth. The mother is probably growing increasingly uncomfortable. Having begun as a single cell her baby is now heavy and cramped. She is also a considerable drain on her mother and putting on fat as using up more resources than the mother can provide. It's time to emerge.
Some scientists argue that there is very little difference between the brain of a newborn baby and that of a 33-week-old fetus. Well, once it seemed that the mental development of a baby began at birth. Now it appears that birth could be a relatively insignificant event in developmental terms. She may have to support herself after birth, but as for the process of thinking, learning and remembering she has already been hard at it for 3 months, and her brain will continue to grow at the same rate for the next year.
The final phase of pregnancy is a demanding one for the mother. Many women feel uncomfortable during the last couple of months. The weight of the baby together with pressure on the spine and the battle for space can all cause her back and legs to ache. She may be feeling anxious about the birth and is likely to be short of breath as her lungs struggle to absorb 20 percent more oxygen than normal.
One of the many things revealed by the 4-D scans is the fact that babies have rapid-eye-movement sleep. This is a period of sleep when the eyes flicker around behind the eyelids. Later in life, this is an indication of dreaming. This gentle flicker of an eye could be a sign that the fetus, still with a month to go before being born, is already dreaming. There was so little life experience. It's hard to imagine what she's dreaming about, perhaps playing with her feet or maybe the gurgling of her mother's stomach.
In just over 8 months, the brain has grown approximately 100 billion neurons with 100 trillion connections. The brain and head have grown as big as they can in the womb, yet they are still small enough to squeeze through the mother's pelvis. The fetus can survive if born any time from about 35 weeks without much medical help. Although the longer she stays inside, the healthier she will be at birth. The mother is probably growing increasingly uncomfortable. Having begun as a single cell her baby is now heavy and cramped. She is also a considerable drain on her mother and putting on fat as using up more resources than the mother can provide. It's time to emerge.
DC 2007-05-04, In The Womb 子宫日记 15
But sometimes things do go wrong. This 26-week-old fetus has developed a hole in his diaphragm, the membrane that separates the lungs from the abdomen. (Baby is facing a completely wrong position.) It's not a problem now but his intestines will grow into the lung cavity which will stop the lungs from developing properly. When he's born, he will almost certainly be unable to breathe and will die. Professor Kiklers Nicoladis is a world-renowned pioneer of fetal surgery at King's College Hospital in London. He's developed a technique to block the windpipe of fetus with an inflatable bladder which forces the intestines back where they belong and allows the lungs to develop properly.
This surgical procedure relies on a fetoscope to operate on the fetus inside the womb. A fetoscope is a long narrow tube filled with fiber optic filaments. Light travels down one side of fibers to illuminate inside the uterus and is sent back to a camera so the surgeon can see what he's doing. It also carries the delicate instruments to conduct the operation. The first step is to inject an anesthetic into the fetus to keep it from moving. The mother is awake during the entire procedure with only a local anesthetic to numb her. A general anesthetic will be too harmful for the baby. Professor Nicoladis then inserts the fetoscope through an incision in the mother's abdomen into the amniotic cavity.
Once he safely reaches the fetus, he gently pushes the fetoscope into the mouth and down the back of the throat. Inside the trachea, he inflates a tiny balloon that traps fluid inside the lungs. As the fetus grows, the lungs produce more fluid which stimulates the lung tissue to grow and expand forcing the intestines out of the chest cavity. The balloon is left in place for two months to give the lungs time to mature. Then the procedure is repeated and the balloon is removed in time for what everyone hopes will be a normal birth. Since this operation to treat babies with this defect has been available, it has increased their chance of survival by 50 percent. At 28 weeks or 7 months, the baby is over 2/3 of the way through her time in the womb and is gaining weight fast as she lays down a layer of fat under her skin. Her senses are buzzing and her cerebral cortex has matured enough to support consciousness.
Over the next four weeks, her nervous system will become as advanced as a newborn baby. She is becoming aware of the world around her and for the first time her brain is beginning to create memory. (Now, we were really screaming. First, I thought...) The fetus has spent so much time listening to her mother's voice, she is familiar with its rhythms. (...going to her mother, and talk agree.) With this constant exposure, she absorbs enough of these patterns to recognize and even respond to it. Researchers analyzing the cries of the newborns found that they already contain some of the rhythms and patterns of their mothers' speech. (Yeah, you can find.) The fetus can now hear, taste, smell and touch.
This surgical procedure relies on a fetoscope to operate on the fetus inside the womb. A fetoscope is a long narrow tube filled with fiber optic filaments. Light travels down one side of fibers to illuminate inside the uterus and is sent back to a camera so the surgeon can see what he's doing. It also carries the delicate instruments to conduct the operation. The first step is to inject an anesthetic into the fetus to keep it from moving. The mother is awake during the entire procedure with only a local anesthetic to numb her. A general anesthetic will be too harmful for the baby. Professor Nicoladis then inserts the fetoscope through an incision in the mother's abdomen into the amniotic cavity.
Once he safely reaches the fetus, he gently pushes the fetoscope into the mouth and down the back of the throat. Inside the trachea, he inflates a tiny balloon that traps fluid inside the lungs. As the fetus grows, the lungs produce more fluid which stimulates the lung tissue to grow and expand forcing the intestines out of the chest cavity. The balloon is left in place for two months to give the lungs time to mature. Then the procedure is repeated and the balloon is removed in time for what everyone hopes will be a normal birth. Since this operation to treat babies with this defect has been available, it has increased their chance of survival by 50 percent. At 28 weeks or 7 months, the baby is over 2/3 of the way through her time in the womb and is gaining weight fast as she lays down a layer of fat under her skin. Her senses are buzzing and her cerebral cortex has matured enough to support consciousness.
Over the next four weeks, her nervous system will become as advanced as a newborn baby. She is becoming aware of the world around her and for the first time her brain is beginning to create memory. (Now, we were really screaming. First, I thought...) The fetus has spent so much time listening to her mother's voice, she is familiar with its rhythms. (...going to her mother, and talk agree.) With this constant exposure, she absorbs enough of these patterns to recognize and even respond to it. Researchers analyzing the cries of the newborns found that they already contain some of the rhythms and patterns of their mothers' speech. (Yeah, you can find.) The fetus can now hear, taste, smell and touch.
DC 2007-05-02, In The Womb 子宫日记 14
The baby's heart beats about twice as fast as her mother's. Monitoring her heartbeat gives a good indication of her general condition. The mother's heart rate and blood pressure are directly affected by her emotional state. If she's calm, her heart slows down and her blood pressure drops. If she's tense and stressed, her heart beats faster and her blood pressure rises.
Although the fetus has her own separate blood supply, these increases in heart rate and blood pressure are easily passed through the placenta and have a direct impact on the baby. It takes a while for the effects to filter through, but when the mother is recovering from the impact of stress and her heat rate is returning to normal, her baby's heart begins to race, as the physiological effects of stress creep through the placenta.
In the short term, stress in the mother can lead to low birth weight or premature birth. But it's also possible that the mother's prolonged anxiety and stress can be passed on, establishing a tendency for stress in the child, and making her more likely to develop chronic health problems, such as heart disease and diabetes. It can even have a harmful effect on the child's mental development in the early years of her life.
By now, the mother can feel her baby move every day. Usually, it's the fetus kicking or pushing. But sometime she may feel the regular twitch of her baby's hiccups. Hiccups are an involuntary sudden contraction of the diaphragm. Why fetus has hiccup is a bit of a mystery. One theory is that it's a reflex that may help a baby latch on to a nipple and feed. The spasm of a fetus's hiccup is strong enough to feel. But unlike our own hiccups, it makes no sound at all. The sound of an adult hiccup is made by the sudden rush of air that's stopped by the closure of the vocal cords. But in the fetus's lungs, there is no air, hence, no hiccup sound.
The last of the major organs to form are the lungs. The lungs don't function during the time in the womb. All the fetus's oxygen is delivered from the mother's blood via the placenta. Inside the fetus's lungs, the branching network of tubes is filled with amniotic fluid during the entire time in the womb. And the tiny air sacs that will extract oxygen from the air remain closed. But the fetus still makes breathing movements with her lungs and diaphragm. This strengthens the chest muscles, so they are ready to expand and fill the lungs with air the moment the baby is born. Most fetuses that reach 26 weeks will make it through to birth with no problem. They simply put on weight and continue to exercise their reflexes and senses.
Although the fetus has her own separate blood supply, these increases in heart rate and blood pressure are easily passed through the placenta and have a direct impact on the baby. It takes a while for the effects to filter through, but when the mother is recovering from the impact of stress and her heat rate is returning to normal, her baby's heart begins to race, as the physiological effects of stress creep through the placenta.
In the short term, stress in the mother can lead to low birth weight or premature birth. But it's also possible that the mother's prolonged anxiety and stress can be passed on, establishing a tendency for stress in the child, and making her more likely to develop chronic health problems, such as heart disease and diabetes. It can even have a harmful effect on the child's mental development in the early years of her life.
By now, the mother can feel her baby move every day. Usually, it's the fetus kicking or pushing. But sometime she may feel the regular twitch of her baby's hiccups. Hiccups are an involuntary sudden contraction of the diaphragm. Why fetus has hiccup is a bit of a mystery. One theory is that it's a reflex that may help a baby latch on to a nipple and feed. The spasm of a fetus's hiccup is strong enough to feel. But unlike our own hiccups, it makes no sound at all. The sound of an adult hiccup is made by the sudden rush of air that's stopped by the closure of the vocal cords. But in the fetus's lungs, there is no air, hence, no hiccup sound.
The last of the major organs to form are the lungs. The lungs don't function during the time in the womb. All the fetus's oxygen is delivered from the mother's blood via the placenta. Inside the fetus's lungs, the branching network of tubes is filled with amniotic fluid during the entire time in the womb. And the tiny air sacs that will extract oxygen from the air remain closed. But the fetus still makes breathing movements with her lungs and diaphragm. This strengthens the chest muscles, so they are ready to expand and fill the lungs with air the moment the baby is born. Most fetuses that reach 26 weeks will make it through to birth with no problem. They simply put on weight and continue to exercise their reflexes and senses.
DC 2007-04-30, In The Womb 子宫日记 13
In normal circumstances, there is no need for the scanning probe to go anywhere near the ear, but if the baby becomes at all unhappy she can easily wriggle away from the sound. Just as in this 4D scan, doctors have observed fetus's grimace and frown as they manipulate the fetus through the mother's abdomen, all part of the delicate expansion of the senses. During the final trimester, the fetus prepares for life outside the womb away from her comforting cocoon and its built-in life support. Many of the crucial tricks and skills she needs to survive on the outside are innate reflexes that she develops inside the womb.
From the 26th week, babies spend about 90 percent of their time sleeping, and when they sleep nothing can wake them. For the other 10 percent of the time they are awake and alert ready for whatever might happen next. They may react to sudden sounds with the startle reflex flinging their arms and legs out to the side. The startle reflex is thought to have originated at a time when we were more at a risk of being eaten. A sudden noise or touch from a predator triggers the reflex and causes the arms to fling out to the side in what may be an attempted self-preservation. This may not be so relevant to our lives today, but other reflexes are crucial to survival after birth.
In this 4D image, the fetus swallows amniotic fluid. During this trimester, she will swallow a pint of fluid every day. By drinking, the fetus helps maintain the liquid balance in the womb. It also helps her digestive system develop properly. But from the moment she is born and the cord is cut she needs to have perfected the art of taking food from her mouth to her stomach.
Along with swallowing one of the most important reflexes to perfect before birth is sucking. Anything vaguely nipple-size that comes close to her mouth triggers her attempts at the sucking reflex. This fetus, 25 weeks old, first sucked its thumb at about 11 weeks at which time it may have already begun to develop a lifelong preference for one hand or the other. Ultrasound scans have shown that as soon as thumb sucking begins, a fetus tends to show a clear preference for either the left or right thumb. This left or right handedness which stays with it for life develops in the womb rather than during early childhood as was previously thought.
At 26th weeks, the fetus measures almost 10 inches from head to toe. She is growing fast and as she moves through the third trimester towards birth, the fetus will triple her weight and double her length. The brain and nervous system will continue to grow dramatically. And soon the fetus will create something even more remarkable. At 26th weeks, the baby's parents may enjoy a pleasant surprise. Now it's possible to hear the fetal heartbeat just by putting an ear to the mother's abdomen. ("Is she kicking?")
From the 26th week, babies spend about 90 percent of their time sleeping, and when they sleep nothing can wake them. For the other 10 percent of the time they are awake and alert ready for whatever might happen next. They may react to sudden sounds with the startle reflex flinging their arms and legs out to the side. The startle reflex is thought to have originated at a time when we were more at a risk of being eaten. A sudden noise or touch from a predator triggers the reflex and causes the arms to fling out to the side in what may be an attempted self-preservation. This may not be so relevant to our lives today, but other reflexes are crucial to survival after birth.
In this 4D image, the fetus swallows amniotic fluid. During this trimester, she will swallow a pint of fluid every day. By drinking, the fetus helps maintain the liquid balance in the womb. It also helps her digestive system develop properly. But from the moment she is born and the cord is cut she needs to have perfected the art of taking food from her mouth to her stomach.
Along with swallowing one of the most important reflexes to perfect before birth is sucking. Anything vaguely nipple-size that comes close to her mouth triggers her attempts at the sucking reflex. This fetus, 25 weeks old, first sucked its thumb at about 11 weeks at which time it may have already begun to develop a lifelong preference for one hand or the other. Ultrasound scans have shown that as soon as thumb sucking begins, a fetus tends to show a clear preference for either the left or right thumb. This left or right handedness which stays with it for life develops in the womb rather than during early childhood as was previously thought.
At 26th weeks, the fetus measures almost 10 inches from head to toe. She is growing fast and as she moves through the third trimester towards birth, the fetus will triple her weight and double her length. The brain and nervous system will continue to grow dramatically. And soon the fetus will create something even more remarkable. At 26th weeks, the baby's parents may enjoy a pleasant surprise. Now it's possible to hear the fetal heartbeat just by putting an ear to the mother's abdomen. ("Is she kicking?")
DC 2007-04-27, In The Womb 子宫日记 12
At three months old, the fetus' most developed sense is hearing. The fetus may be completely surrounded by amniotic fluid, but because sound travels through fluid about four times faster than it does in air she has plenty to hear. The first sounds the fetus hears as her ears start picking up vibrations at 13 weeks are the gurgles and rumbles made by her mother's body. A succession of hiccups, burps, bubbles, sloshes and slurps marks the passage of food, liquid and air in, out and through the maze of passages and tubes just inches from the baby's ears.
The fetus also makes her own noises as she kicks and swishes in the amniotic fluid. She can also hear the competing flutter of heartbeats, her own racing at twice the speed of her mother's, both her constant companions during her time in the womb. The fetus can also hear sounds from the world outside: conversations, loud noises and music. The walls of the womb, together with the abdomen, act to filter out most of the high frequencies. All sounds reach the fetus distorted, but higher sounds are more muffled. Only the lower-bass notes of a piece of music have much impact.
Voice's sound is distorted too. Vowels are generally lower in pitch than consonants, so the fetus only hears the melody of speech without the percussion of consonants. The sound of the mother's voice is different from any other since it travels directly through the fluids of the body. This may help the baby develop the unique relationship it has with its mother. (Excellent, good luck, see you later, bye.)
Other voices like the father's must pass through air, then fluid and may not cut through the general background noise. (See, a little face there.) The loudest sound a fetus will ever hear may come during an ultrasound scan. It's impossible to hear the actual ultrasound waves. They are far too high at frequency to affect the human ear, but the ultrasound can cause secondary waves in the amniotic fluid that the baby can hear.
To produce finely-detailed images, ultrasound probes fire a rapid succession of pulses, each lasting less than one millionth of a second. The rapid switching on-and-off of these pulses can cause waves in the fluid which sound like a high-pitch tapping. If the probe is pointed directly at the baby's ear, it can sound as loud as a subway train.
The fetus also makes her own noises as she kicks and swishes in the amniotic fluid. She can also hear the competing flutter of heartbeats, her own racing at twice the speed of her mother's, both her constant companions during her time in the womb. The fetus can also hear sounds from the world outside: conversations, loud noises and music. The walls of the womb, together with the abdomen, act to filter out most of the high frequencies. All sounds reach the fetus distorted, but higher sounds are more muffled. Only the lower-bass notes of a piece of music have much impact.
Voice's sound is distorted too. Vowels are generally lower in pitch than consonants, so the fetus only hears the melody of speech without the percussion of consonants. The sound of the mother's voice is different from any other since it travels directly through the fluids of the body. This may help the baby develop the unique relationship it has with its mother. (Excellent, good luck, see you later, bye.)
Other voices like the father's must pass through air, then fluid and may not cut through the general background noise. (See, a little face there.) The loudest sound a fetus will ever hear may come during an ultrasound scan. It's impossible to hear the actual ultrasound waves. They are far too high at frequency to affect the human ear, but the ultrasound can cause secondary waves in the amniotic fluid that the baby can hear.
To produce finely-detailed images, ultrasound probes fire a rapid succession of pulses, each lasting less than one millionth of a second. The rapid switching on-and-off of these pulses can cause waves in the fluid which sound like a high-pitch tapping. If the probe is pointed directly at the baby's ear, it can sound as loud as a subway train.
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