El desarrollo de gemelos y trillizos en el vientre materno es un fenómeno asombroso que nos revela los misterios de la vida prenatal. En este documental educativo, exploraremos cómo se forman los gemelos y trillizos, así como los desafíos y maravillas que enfrentan durante su gestación. Desde la fertilización hasta el parto, cada etapa del desarrollo es crucial y única. Analizaremos las diferentes configuraciones de los gemelos: dicigóticos y monocigóticos, y cómo su entorno en el vientre materno influye en su crecimiento y salud. También discutiremos la importancia de los cuidados prenatales y las tecnologías modernas que permiten un mejor seguimiento de los embarazos múltiples. Acompáñanos en este viaje fascinante que no solo educa, sino que también celebra la vida desde sus inicios. Entender el proceso de desarrollo en el vientre materno no solo es crucial para los futuros padres, sino también para cualquier persona interesada en la biología humana y la maternidad. Descubre cómo la ciencia y la naturaleza se entrelazan para dar vida a estas extraordinarias experiencias.
**Hashtags:** #Gemelos #Trillizos #VidaPrenatal
**Keywords:** gemelos, trillizos, vientre materno, desarrollo prenatal, embarazo múltiple, cuidados prenatales, biología humana, fertilización, maternidad, documentales educativos
**Hashtags:** #Gemelos #Trillizos #VidaPrenatal
**Keywords:** gemelos, trillizos, vientre materno, desarrollo prenatal, embarazo múltiple, cuidados prenatales, biología humana, fertilización, maternidad, documentales educativos
Categoría
😹
DiversiónTranscripción
00:00But in this case, something even more extraordinary happens.
00:05The fertilized egg splits in two, creating two twins.
00:10The fertilized egg is born.
00:15The fertilized egg is born.
00:20The fertilized egg is born.
00:26The fertilized egg splits in two, creating two identical twins.
00:33Then each one splits again.
00:36Something that happens once every 64 million.
00:42They are identical quads.
00:47For the first time, the new and revolutionary techniques of creating images
00:52allow us to follow in detail three very different pregnancies.
01:00Identical twins.
01:04Triplets conceived on different days.
01:09And some spectacular quadruplets.
01:15Through them, we will delve into the greatest wonder in the history of human reproduction science.
01:22The miracle of multiple births.
01:27In the mother's womb.
01:45Twins, triplets and quadruplets.
01:55This girl is about to be born.
02:01But for her, her stay in the mother's womb has not been a pleasant journey.
02:08After her birth, it will not be the first time she meets other humans.
02:18She has been sharing her space not with one, but with three sisters.
02:31Each grew up from a smaller egg than a grain of sand.
02:38Lonely and ignorant.
02:43They have been touching each other.
02:46Reacting to each other.
02:51Even doing something that looks like a kiss.
02:58They have all fought for space and sustenance.
03:05However, they have laid the foundations for a life of warmth, comfort and companionship.
03:15They have also helped each other.
03:18And they have forged a connection and some patterns of conduct that will define them for the rest of their lives.
03:35As for most of us, the journey begins with the act of conception.
03:44During which an adult and healthy male releases approximately 300 million sperm in the woman's vagina.
03:56The sperm will go through the reproductive tract towards the fallopian tubes.
04:01Where the prize is.
04:05An egg without fertilization.
04:08During its reproductive cycle, a woman usually releases an egg.
04:15The first sperm that reaches it and manages to enter through its outer layer will be the winner.
04:27Once inside, the sperm head, which contains the father's DNA, and the nucleus of the egg, where the mother's DNA is,
04:36join through small fibers called centrosomes.
04:45The two DNA games merge.
04:49The conception has taken place.
04:54And this is the first cell of what will be a new human being.
05:02Day 1.
05:04In its first hours, the fertilized egg begins its journey down through the fallopian tube towards the uterus.
05:13A day later, it has already been subdivided once.
05:19The second day we have between two and four cells.
05:25The third, eight.
05:31Day 5.
05:32The fifth day, the embryo, which is now called blastocyst, has between 70 and 120 cells distributed in two differentiated sections.
05:43The inner cellular mass will be the body.
05:48The exterior, which is ring-shaped and is called trophectoderm, will become the placenta.
05:55A vital part.
06:02Around the sixth day, the blastocyst finally comes out of the shell of the egg and adheres to the uterus, where it begins to grow.
06:15Here it will remain for the next 39 weeks, going from blastocyst to embryo.
06:23From embryo to fetus.
06:27And from fetus to full baby.
06:37But in a few cases, approximately one in every 250, the egg performs an extraordinary operation.
06:49It splits in two.
06:50It duplicates, giving rise to the separated fertilized eggs.
06:55Separated, but identical.
07:04No one fully understands why this happens.
07:09But the very nature of the egg could give us a clue.
07:17Most identical twins are conceived by women who are well at the beginning, well at the end of their fertile years.
07:29Some scientists believe that the ovules of older women are weaker and therefore more likely to split.
07:40What we know for sure is that this has to happen in the first 14 days after conception.
07:46Otherwise, it would not happen.
07:56Identical twins have one of the closest biological relationships known.
08:02They will grow up looking alike and having similar voices, but they are not perfect replicas.
08:11A small number of the maternal ovule's genes are located outside its nucleus.
08:19Known as mitochondrial DNA, these genes can mutate after the ovule is subdivided,
08:28subtly altering the development of the embryo.
08:34As the twins grow and reach maturity,
08:38small differences in height, constitution, and even personality will become more and more evident.
08:49This is why, nowadays, some scientists avoid the term identical,
08:54and prefer to use monozygotic twins or uniovular twins.
09:04Our uniovular identical twins settle in the ovule around the sixth day.
09:13Like the single embryos, each of them will develop inside two sacs.
09:19One outside, the corion, which is attached to the placenta,
09:24and the inside, known as the amniotic sac.
09:29Both will merge.
09:33Some twins share a corion, and very few of them have the same amnion.
09:42As they grow up, they will compete for their mother's space and nutrition.
09:48But despite this, they will also share a very deep and lasting bond.
09:55This woman, Julie, is very atypical.
10:00Although she doesn't know it, her fertilized ovule has split, not in two, but in four.
10:14She is probably one of the few pregnant women in the world with identical quadriplegics.
10:21Something that happens once every 64 million years.
10:29These tiny fetuses each have their own amnion,
10:33but they share the corion, and with it, the placenta.
10:38The consequence of this is that for 30 weeks,
10:42they will have the same source of oxygen and nutrition.
10:47From a biological point of view,
10:50they are some of the closest individuals that the human body is capable of conceiving.
11:00Rachel, another mother, will go through a totally different process.
11:06She has released two eggs.
11:09One from each ovary, fertilized by different sperm.
11:15She is pregnant with twins, also called biovulars or dizygotic.
11:23It's as if two pregnancies had started on the same day.
11:30Unlike the identical ones,
11:33the twins are not genetically more different than the siblings
11:37that share half of their genes.
11:45Rachel is a mother of four,
11:48and she is pregnant with twins.
11:52They share half of their genes.
11:59Day 7
12:01All of our ovules are implanted in the uterus.
12:07In the next few days,
12:09the blastocyte begins to enter the uterus lining,
12:14which is currently swollen by the hormones.
12:20This small army of cells invades the uterus,
12:24and little by little,
12:26its members split in two to form the primary bonds
12:29between the placenta and the bloodstream of the mother.
12:37Among the changes that occur in the blastocyte cells,
12:42the first of them is the configuration of two layers.
12:50Around the ninth day,
12:52these layers have become a disk with a cavity at the top,
12:57the future amniotic sac,
13:00and another one at the bottom, the vitelline sac.
13:09Halfway between them,
13:11a crevice called the primitive line appears.
13:16They go towards it,
13:18and over it, the cells precipitate.
13:30Two weeks later,
13:32at one end of the primitive line,
13:35another spot known as the organizer is formed.
13:40Up to this moment,
13:42the cells in the body had all been the same.
13:48They are the mother cells.
13:53Now each one flows over the organizer,
13:56who assigns them their destiny.
14:01Some will be part of a limb,
14:05some will be part of a limb,
14:07some will be part of a hand,
14:10and some will be part of a crystal eye.
14:16The crest of this little embryo
14:18does not yet look like a head.
14:21But at 15 days,
14:23the nervous cells begin to configure what will later become the brain,
14:27as well as the spinal cord.
14:31Both organs are completely exposed and unprotected by skin or bones.
14:36One of the first to form is the heart.
14:40Until now,
14:41there had been a lot of dormant muscle cells.
14:47But later,
14:48around the 22nd,
14:50a cell contracts spontaneously,
14:55and begins a chain reaction in the rest of the body.
15:00The whole body begins to beat.
15:06At first,
15:07it pumps primitive blood cells,
15:09no thicker than hair,
15:11which transports the vital food and oxygen supplies for growth.
15:17Later,
15:18when the brain has developed,
15:20it will control the rhythm of the contractions,
15:23increasing the speed when it needs more energy.
15:27And slowing down when the body rests.
15:32Throughout life,
15:33a heart beats 3 billion times.
15:46This 32-year-old woman is Jennifer.
15:51A year ago,
15:53her body created an egg that was later fertilized.
16:03Then it split in two to form identical twins.
16:09But the story doesn't end there.
16:13Later,
16:14Jennifer released another egg that was also fertilized.
16:20A third brother joined the identical twins.
16:32This process is known as super-fertilization.
16:36In Latin,
16:37it means additional fertilization.
16:42It's something very unusual.
16:47In Jennifer's case,
16:48the second egg was fertilized
16:50by the surviving sperm of the first penetration.
16:56But this is not always the case.
17:01Technically,
17:02each egg could have been fertilized by the sperm of two ejaculations.
17:08Or even different men.
17:15It is estimated that out of every 400 pairs of twins,
17:20one is made up of two siblings of different parents.
17:24Week 6.
17:26Our three groups of embryos have reached their sixth week.
17:31They measure almost two and a half centimeters.
17:35Now,
17:36the eyeball is made up of 85%.
17:40And we can see the beginning of some rudimentary crystals.
17:47In this phase,
17:48the uterus can contain many fetuses.
17:51The record is 15,
17:52although the number of live births has not exceeded 9.
17:57In this echograph,
17:58we can see five fetuses of a few weeks old.
18:04Although Jennifer's triplets were conceived naturally,
18:08perhaps as a result of a super fertilization,
18:11most of the multiple pregnancies
18:13occur thanks to modern fertility treatments.
18:21In some cases,
18:22the woman takes drugs to stimulate the production of ovules,
18:26some of which end up being fertilized through sex.
18:36In other cases,
18:37we use in vitro fertilization.
18:44Here,
18:45the ovules are fertilized outside the ovary,
18:47in a petri dish,
18:49and then they are inserted into the uterus.
18:57Since the beginning of fertility treatments in the 1970s,
19:02the number of twins has increased by 50%.
19:05And the number of triplets and quadruplets has multiplied by more than four.
19:11Second month.
19:19The embryos are eight weeks old.
19:26Now they are three centimeters long,
19:29the size of the tip of the thumb.
19:35The eyeball is finished.
19:38The crystalline almost as well,
19:40but the muscle that will allow it to function has not yet grown,
19:45and will not be useful until the sixth month.
19:52In two weeks, the fetus will have eyelids.
19:58The head,
19:59one of the first structures that grow,
20:01is huge.
20:03It is one third the size of the fetal body.
20:08The embryo begins to resemble a small human.
20:12From now on,
20:13it is known as fetus,
20:15from the Latin word that means baby.
20:24Week nine.
20:29In the ninth week, the brain develops rapidly.
20:37Each minute creates an average of two and a half million cells,
20:41which is equivalent to 100 billion at birth.
20:54It is now when the body begins to move.
21:03These movements consist of involuntary spasmodic reflexes
21:08that the brain still does not control.
21:14This phenomenon plays a vital role
21:16in stimulating muscle growth
21:18and strengthening the joints.
21:25The heart acquires greater speed.
21:29When it began to beat the third week,
21:31it was at a rate of 75 beats per minute.
21:35Gradually, the speed increases,
21:37and in the ninth week,
21:38it beats at a frenetic rate of 165 beats per minute.
21:43It is its maximum speed.
21:46During the second half of the pregnancy,
21:48its rhythm will slow down
21:50until it reaches between 125 and 150 beats per minute.
21:55A child's heart beats an average of between 70 and 100 beats per minute.
22:00An adult's heart beats between 70 and 80 beats per minute.
22:09Week ten.
22:14Between the tenth and the fourteenth week,
22:17the pregnant women undergo their first ultrasound.
22:28Ultrasounds have revolutionized our understanding of fetal development.
22:39These images are produced by high-frequency waves,
22:43too high for us to perceive,
22:47emitted from a probe into the womb.
22:58The vibrations penetrate the soft tissue,
23:01but bounce off when they collide with denser structures,
23:04such as bones.
23:06From the pattern they form,
23:08the computer creates an image of the hidden fetus.
23:15Until now, the image of the ultrasound was flat,
23:18two-dimensional.
23:20But new technology allows us to see images in three dimensions
23:24in a temporal sequence,
23:26which produces four-dimensional or 4D ultrasounds.
23:36Week eighteen.
23:41We have reached the eighteenth week,
23:43half of the gestation.
23:46At this point, we are approaching the stage
23:49when the senses of our fetuses begin to develop for real.
23:55The digestive system also begins to function.
24:00Although they receive all the support they need directly in their blood flow
24:04and through the placenta,
24:07they have to be able to swallow and digest
24:09from the moment they are born.
24:15For this reason, their mouths open
24:17and the fetuses drink part of the amniotic fluid that surrounds them.
24:26This 4D image shows their first efforts.
24:34Some of the flavors of the food consumed by the mother
24:37travel to the placenta,
24:39enter the bloodstream of the fetuses
24:42and exit the amniotic fluid.
24:54The fetuses taste,
24:56and thus develop their taste buds.
25:03With their senses developing simultaneously,
25:06the fetuses are about to use them.
25:11The twins and other babies of multiple pregnancies
25:13exhibit a particularly peculiar behavior.
25:19Scientists have witnessed them playing together.
25:30Day 20
25:33Twenty weeks have passed since the gestation.
25:38The fetuses measure 14 centimeters,
25:41so small that they fit in the palm of their mothers' hands.
25:49They still cannot open their eyes,
25:51although the structure of the eyeball is already formed.
25:56The iris, which controls the amount of light they receive,
25:59is growing,
26:01but the pupil will not form until the moment of birth is near.
26:08The fifth month is an important time for the nervous system.
26:12The number of nervous cells increases rapidly.
26:16Two and a half million new neurons every minute.
26:21100 billion at birth.
26:26Their main task is to grow,
26:31although this is about to become their biggest problem.
26:38The uterus can contain a fetus weighing up to five and a half kilos.
26:47Normally, single babies weigh between two and a half kilos
26:50and five and a half kilos at birth.
26:54Twins weigh between two and almost three kilos.
26:59And triplets between one and a half and two and a quarter.
27:05As for quadruplets,
27:07sometimes they are born weighing only one kilo each
27:10and need to spend several weeks in intensive care.
27:16The taller a woman is,
27:19the longer her abdomen and the greater the weight she can bear.
27:24Week 24.
27:26We have reached 24 weeks of development.
27:31At this time, the lungs secrete surfactant,
27:35which helps babies breathe when they are born.
27:38It is a gelatinous substance
27:40that allows the lungs to separate while inspiration occurs.
27:45Because quadruplets are almost always premature,
27:48doctors prescribe a steroid to the mother
27:51that helps the formation of the surfactant.
27:56Because quadruplets are almost always premature,
27:59doctors prescribe a steroid to the mother
28:02that helps the formation of the surfactant.
28:06But for the first time,
28:08their mother will be able to see them interact.
28:15Although only one appears on the screen,
28:18sometimes we can see the extremity of another.
28:28These 4D images show how one pushes the other.
28:40Even the twins, who are in separate corneas,
28:43feel that their brothers are taking their place.
28:53The womb is running out of space.
28:58Our twins are about to start
29:00one of the most fascinating prenatal activities.
29:05Games.
29:10And even more.
29:12Some of these games seem to continue after birth.
29:25In one case, a pair of twins used to put their cheeks together,
29:29each one to one side of their corneas.
29:41When they were a year old,
29:44their favorite game was to put each one
29:47to one side of a curtain
29:50and laugh every time they touched each other through the cloth.
29:58Scientists believe that they simply extended
30:01their prenatal behavior to early childhood.
30:06Week 26.
30:09After 26 weeks of prenatal care,
30:12the eyes suddenly open
30:14when the eyelids are separated for the first time.
30:19Some researchers believe that now the babies can see.
30:24In the dark, the fetuses could be able
30:27to distinguish the silhouettes of their siblings.
30:30However, single babies have a more limited vision.
30:33But the twins can contemplate many more things
30:36when, from time to time, the light penetrates the uterus.
30:42The middle and internal ears,
30:44which have been growing since the fourth week,
30:47are completely formed and can function.
30:52The fetuses can hear the heartbeat of their mother
30:55and the sounds of the amniotic fluid.
31:01They can also perceive the noises of the outside world,
31:05including music and voices.
31:10Week 28.
31:13We have reached the 28th week.
31:20Now, one of the things
31:22that doctors pay more attention to is the umbilical cord.
31:28This masterpiece of nature is thick and resistant.
31:34It contains two arteries and a vein,
31:37twisted in such a way that no knots are made.
31:48Even if the cord is wound around the neck,
31:51it can supply the baby with nutrients
31:55But for the twins who share the amniotic sac,
31:58this life-saving line is also a great danger.
32:04Identical twins can be trapped in the other's cord
32:08and interrupt the flow of blood and oxygen,
32:11either for themselves or for their siblings.
32:16This ultrasound shows a twisted cord.
32:31The reason identical twins
32:33who share the same amniotic sac
32:35are often illuminated by cesarean section
32:38is to reduce the risk of being trapped in the cord.
32:43In the last few weeks before birth,
32:45babies are putting on as much weight as they can.
32:49The bigger and fatter they are, the better.
32:54While doctors monitor the health of fetuses from the outside,
32:59they can also regulate and control their development
33:03by monitoring the growth of the fetus.
33:09If one of the twins does not receive enough blood in the uterus,
33:13its body will take measures to preserve its most important part,
33:17the brain.
33:22In fact, it is able to regulate the volume of blood
33:25that the different parts of its body receive.
33:29In this case, the volume of blood in the uterus
33:34is reduced by pumping less blood to the extremities,
33:36which do not need it so much,
33:38and more to the brain,
33:40to prevent it from being damaged by lack of food.
33:46Week 30
33:50At 30 weeks, the fetuses have everything in place.
33:57Some details, such as the eyelashes, have already been formed.
34:03For single babies, the last 10 weeks consist of one thing,
34:08to grow.
34:14But this is not so easy for the multiples,
34:17because there is no more space for them to grow.
34:22Babies compete for the space by pushing themselves.
34:30Their eyeballs move and react to light.
34:38If they are not able to move,
34:42they will not be able to grow.
34:49If an intense light is projected on the abdomen,
34:54it has been observed that the babies react.
35:01Week 32
35:04For single babies, they have eight weeks to go.
35:08But for our triplets, the big moment is much closer.
35:15All triplets face a medical challenge.
35:21The delicate balance between a sufficiently long pregnancy,
35:25so that they have a sufficient size at birth,
35:28but not so prolonged that it puts the mother or the babies in danger.
35:35It is essential that the lungs have matured
35:38so that the newborns can breathe for themselves.
35:4534 weeks is an ideal period for triplets.
35:53Due to the dangers of natural birth,
35:55doctors recommend a cesarean section.
36:00In the case of Jennifer,
36:01the doctors decide not to wait and opt for 32 weeks.
36:08Jennifer has chosen local anesthesia.
36:12As she does not feel pain in the abdomen,
36:14she will be conscious all the time.
36:20The surgeon prepares to perform the first incision.
36:25Inside, the babies do not know what is going to happen.
36:34Cesareans are always done quickly to reduce the risk of complications.
36:40The surgeon cuts the membrane.
36:46The first baby is born.
36:49It is one of the identical twins, a male.
36:53The baby breathes and shouts for help.
36:59The cord of the placenta,
37:01its life insurance for eight months, is cut.
37:07Without pausing, the surgeon looks for the other twin,
37:10which is in the same corionic sac.
37:17This one comes out quickly.
37:22However, the arrival of his brother is delayed
37:25because he is in his own corionic sac.
37:38Finally, he comes out. Also by the feet.
37:48Despite the abdominal pressure in recent months,
37:51the three babies are strong and healthy.
38:00They weigh them.
38:03Each of them weighs a little more than three kilos.
38:10But they are eight premature weeks.
38:18The sophisticated technology incubators
38:21imitate the welcoming world of the womb
38:23and will help them gain weight and make their lungs mature.
38:28In underdeveloped countries,
38:30babies share the incubators for warmth and comfort.
38:36Week 38.
38:40Rachel's twins are about to be born.
38:44They have spent the last 38 weeks in the womb.
38:50Their lungs are robust and their bodies are ready.
38:59At birth, twins usually weigh a little over two kilos.
39:06Their small bodies make them good candidates for a natural birth.
39:13This is what Rachel wants.
39:16She has had twins before and feels safe and able to give birth naturally.
39:26A hormone causes the birth.
39:29Normally, the baby turns its head down when the pregnancy comes to an end.
39:35With two in the womb, this is more difficult.
39:46The baby whose head is closest to the canal will be the first.
39:55Water breaks.
40:00The baby's head opens up through the remains of the bag that has protected it for nine months.
40:08With the cervix fully dilated,
40:10the uterus muscles continue to push the baby into the outside world.
40:20Rachel has been pushing for three hours.
40:25The first one peeks through the head and Rachel squeezes to get it out.
40:33As is often the case with twins,
40:35the umbilical cord is wound around the neck.
40:38The comadrona immediately unties it.
40:44The first baby is about to be born.
40:47The first baby is about to be born.
40:50The first baby is about to be born.
40:53The first baby is about to be born.
40:56The first baby is about to be born.
41:05It's a boy, and he weighs just over three kilos.
41:08A healthy value for a twin.
41:26For the first time in nine months, this baby has all the womb to himself.
41:49Ten minutes after the first birth, the second baby's head appears.
41:57It follows its brother into the outside world.
42:04It's a girl weighing 2.7 kilos.
42:12After a few minutes of separation,
42:17the quadriplegics have 29 weeks and three days.
42:21So the doctors decide that it's time to operate before the risk is too high.
42:28All the members of the extensive medical team are focused on the mother and her imminent birth.
42:38The surgeon pulls out the abdomen
42:41and tries to locate the first baby,
42:45which opens up through her omnion.
42:58Each one has their own.
43:04A girl weighing just under one kilo.
43:19Then comes her sister, who is just as small.
43:27The team checks the vital signs of each one.
43:31Their main concern is that the babies can breathe without assistance.
43:40These girls were born 11 weeks before the only babies.
43:53The doctor does the third one, the smallest.
43:59He takes her out of the womb and hands her to the midwife to examine her.
44:08There's only one left.
44:11So this extraordinary quadriplegic birth is about to end.
44:30In the end, the fourth and last baby is born.
44:34They're all girls.
44:43It's incredible that they all weigh one kilo,
44:46a quarter of the weight of a single baby.
44:53They'll have to spend several weeks in the incubator until they mature enough to go home.
45:09Rachel's twins are eight weeks old, but have been together for almost a year.
45:17Each one begins to acquire their own personality.
45:23Although they're not identical, they're very similar.
45:27This is partly due to their genes and partly to the time they've spent in the womb.
45:37Although identical twins are much more like each other,
45:41a product of their genetic configuration, their upbringing will also play a role.
45:47Jennifer's twins are already at home.
45:50Now they can breathe on their own.
45:53At this age, they all look the same.
45:57But as they grow up, it's likely that the twins will be different from the identical ones.
46:10Julie's twins are three months old.
46:13They're gaining a lot of weight, even though they were born with just one kilo of weight.
46:22Julie and Jose feed them with a special milk that contains extra calories to speed up their growth.
46:31It took them four weeks to reach their average weight, just three kilos.
46:40Even today, with all the advances in medicine, multiple births are still a miracle.
46:50Although they make up a small proportion of all human births, they fascinate us all.
46:58For science, they're not just a challenge,
47:01but also a window to reproduction that provides a lot of knowledge about the amazing world of the mother's womb.
47:13And for our twins, triplets and quadruplets,
47:17the interactions with their siblings in the womb will unite and define them as they grow up,
47:23providing them with a source of comfort and inspiration for the rest of their lives.