Full transcript
0:02is guaranteed
0:06environment
0:17searching but in this case something
0:20even more extraordinary
0:24happens
0:26the into
0:32then the egg splits again in a rare
0:35event that happens only once in 64
0:38million
0:39pregnancies and idental
0:46quad for the first time
0:51evolutionary rare and risky pregnancies
0:54in intricate
0:56detail it'll be a dangerous Journey for
0:59a pair of ID
1:03twins triplets conceived on different
1:06days and
1:12a into two three or more the transforms
1:17into an Ever shrinking World a place
1:20where siblings resort to unexpected
1:22behavior for
1:26food ultimate of
1:30can the and become the Miracles that are
1:34multiple
1:47births this baby is about to be
1:51[Music]
1:53born but for her the womb has been
1:56anything but calm
1:59[Music]
2:01and birth won't be her first encounter
2:03with
2:04[Music]
2:10humans she's been sharing this space
2:13with
2:20[Music]
2:22but each growing from an egg smaller
2:26grain of land
2:31the system solitary and
2:35unaware but ever space of
2:39their they
2:41touch
2:43react it even like they a friendly
2:50then but don't be fooled they're
2:53competitors for nourishment and
2:57space the found for a life of warmth
3:01comfort
3:07and they've helped each other
3:10develop and their bond and behavioral
3:13patterns will Define them for the rest
3:15of their lives
3:17[Music]
3:24[Music]
3:38[Music]
3:39their Journey Begins With the act of
3:43[Music]
3:47conception a normal Healthy Man releases
3:50about 300 million sperm into a woman's
3:54vagina and the race is on
4:00the sperms swim up the reproductive
4:02tract toward the Fallopian tubes where
4:05the prize
4:07awaits an unfertilized
4:15egg during each reproductive cycle which
4:19lasts between 28 and 32 days a woman
4:22usually releases one egg
4:28[Music]
4:32the first sperm to reach it and
4:33penetrate its outer coating is the
4:36winner but it's no easy
4:39[Music]
4:42task once inside the egg the head of the
4:46sperm containing DNA from the father and
4:49the nucleus of the egg containing the
4:51mother's DNA are brought together by
4:54tiny fibers called centrosomes
5:05then the two sets of DNA
5:11fuse conception is complete this is the
5:15first cell of what will ultimately
5:17become a new human
5:24life to kick off the journey the
5:27fertilized egg travels down the Ian tube
5:30toward the
5:33uterus just 24 hours later it divides
5:37for the first
5:43time on day two it divides into four
5:49cells and on day three into eight
5:56cells by day five the embryo is now a
5:59blast
6:01assy its 70 to 120 cells have formed two
6:05distinct
6:07sections the Inner Cell Mass which will
6:09become the
6:11body and the outer ring shaped section
6:14or Trader is the all important
6:24placenta around day six the blastocyst
6:28hatches through the egg
6:30sh and attaches to the lining of the
6:32uterus where it starts to
6:39burrow it'll remain here for the next 39
6:43weeks growing from blast assist to
6:47Embryo Embryo to
6:51fetus and fetus to fully grown baby
6:56[Music]
7:02well that's how it normally happens but
7:05once in every 250 cases the egg does
7:09something
7:10extraordinary it splits in two
7:13duplicating itself to become two
7:16separate fertilized
7:19eggs separate but
7:27identical no one knows for sure why this
7:33happens but one clue May lie in the
7:35nature of the
7:40eggs typically identicals are conceived
7:43by women who are either at the beginning
7:45or end of their reproductive
7:53years some scientists believe that older
7:56women produce weaker eggs that are more
7:58vulnerable to splitting
8:00[Music]
8:04but if the split hasn't happened within
8:0714 days of conception it never
8:19will identicals share one of the closest
8:23biological Human
8:26Relationships most of them look and
8:28sound almost exactly
8:31alike even though they don't match
8:35[Music]
8:38100% a small number of genes in the
8:41mother's egg known as mitochondrial DNA
8:45sit outside the
8:48nucleus these genes can mutate after the
8:51egg has split and subtly modify the way
8:55each embryo grows
8:59small differences in height build and
9:02even personality will become more
9:05apparent as the twins grow up and reach
9:08maturity a relief for those struggling
9:10to figure out the game of who's who in
9:13an identical world but this is also why
9:17some scientists prefer to use the term
9:20monozygotic or single egg twins instead
9:24of identical
9:26[Music]
9:31identical twins are almost always the
9:33same
9:35sex but there are a tiny number of boy
9:38girl monozygotic
9:41[Music]
9:45twins they result from an egg that
9:47contains an unusual mix of sex
9:50chromosomes not the usual XX for a girl
9:54and XY for a
9:57boy occasionally an egg contains three
10:00sex chromosomes two x's and a
10:06y but if the egg divides to produce
10:09monozygotic twins and a chromosome is
10:11lost in the process one embryo will have
10:14a girl's XX combination and her
10:17monozygotic twin will be an XY
10:23[Music]
10:26boy around day six the single egg
10:29identical twins Lodge in the
10:35womb as with single pregnancies each
10:38will develop inside two
10:40sacs an outer coron attached to the
10:45placenta and an inner amnon or amniotic
10:51sac which fuses over
10:55time some twins share a coron a few even
10:59share an
11:04amnon as they develop they'll compete
11:07for space and nutrition from their
11:10mother but despite this battle in the
11:13womb they may one day share a deep
11:16enduring
11:22bond this is Julie and even though she
11:26doesn't know it her pregnancy just took
11:28an extreme extremely unusual
11:31turn her single egg didn't stop when it
11:35split in two it kept going and split
11:38into
11:40four now she's one of only a handful of
11:43women in the world pregnant with
11:45identical
11:48quads and the chances of this baby Lotto
11:51are only one in 64
11:56million the fetuses each have their own
11:59amnon but they all share a coron and
12:03with it a single
12:06placenta the four of them will share a
12:08single source of food and oxygen for 30
12:11long
12:14weeks biologically they'll be among the
12:17closest set of individuals the human
12:19body can
12:25conceive this woman Rachel faces a compl
12:29completely different
12:32process she released two eggs one from
12:36each
12:38overy and a different sperm fertilized
12:41each
12:46one she's pregnant with fraternal twins
12:50sometimes called double egg or dizygotic
12:55twins it's like two separate pregnancies
12:58occurred on the same
13:05day unlike identicals fraternal are
13:08genetically no different from regular
13:11brothers and sisters who share only half
13:14their genes with each
13:20other day seven all eggs have implanted
13:25in their mother's wombs
13:29over the next few days the blastocysts
13:32embed themselves into the uterine
13:35Linings which are swollen by
13:42hormones the small army of cells invades
13:45the uterus and gradually separates into
13:50two forming the primary connection
13:53between the placenta and the mother's
13:55bloodstream
14:02now comes the first change in the clump
14:05of cells inside the blast
14:10assists first two layers start to
14:19form by day nine the two layers have
14:23become a disc with the future amniotic
14:26sack in the cavity above it
14:29and the future Yol sack in the cavity
14:32[Music]
14:39below halfway down the disc a Groove
14:43appears called the Primitive
14:46streak cells migrate toward the streak
14:49and pour into it
14:53[Music]
15:00by day 14 another patch forms on the
15:03edge of the Primitive
15:05streak it's called the
15:11organizer until this point all the
15:14developing cells in the body have been
15:16the
15:19same they're known as stem
15:24cells now each cell flows over the
15:28organizer to get it assigned its
15:34fate some will become part of a limb
15:37some part of a
15:39hand and some will make up the lens of
15:42an
15:46eye the crest of the tiny embryos don't
15:49resemble heads yet but by day 15 nerve
15:54cells are forming in what will become
15:56their brains and spinal columns
16:00all exposed and completely unprotected
16:03by skin or
16:06bone now the embryos start to come
16:09together with the formation of three
16:12crucial
16:13layers the ectoderm the skin and nervous
16:17system the mesoderm muscles bones and
16:22heart and the endoderm the lining of the
16:25stomach and lungs the liver and pancreas
16:31[Music]
16:39at this stage there's plenty of room for
16:41these primitive embryonic bodies to
16:44develop side by side in the uterus
17:05one of the first organs to form is the
17:08heart which is still a dormant clump of
17:11muscle cells in each
17:16embryo but about 22 days in one cell
17:20spontaneously
17:22contracts triggers its
17:24neighbors and sets off a chain reaction
17:29the hearts suddenly spring to
17:33life they pump primitive blood cells
17:36through veins no thicker than a strand
17:38of hair this blood carries vital
17:41supplies of food and oxygen to fuel the
17:44embryos frantic
17:47growth when their brains are more
17:49developed they'll regulate the rate of
17:52contraction increasing when more fuel is
17:55needed and slowing when their bodies are
17:58at at
18:00rest in the average lifetime a heart
18:03beats 3 billion
18:15times after about a month the developing
18:19embryos of the twins triplets and quads
18:22are less than A4 of an inch long about
18:26the size of a small kidney bean
18:33[Music]
18:37they still have plenty of room to
18:40grow the mother's womb has a capacity of
18:431 and2
18:45gallons similar to the size of a large
18:49[Music]
18:53watermelon the embryos have gills and a
18:57tail remnants of our evolutionary
19:03past they appear at about 4
19:06weeks and vanish by week
19:14six the limb buds extend from the
19:17central trunk of the body
19:23outward the eyes are basic at
19:27best the optic cup which will become the
19:30eyeball is just starting to
19:34form and with it a layer of pigment
19:38appears as a black dot in the
19:44center an opening for a mouth and
19:47passageways that make up the inner ear
19:53appear the outside of the ear hasn't
19:55formed yet
19:58[Music]
20:03at this stage their hearts seem to be
20:06pulsating outside their
20:20bodies 5 weeks into development the
20:23twins are growing fast
20:26[Music]
20:31but while fraternal and identical twins
20:34are the most common types of multiple
20:36births there is
20:42[Music]
20:45another sets that are a mix of both
20:48fraternal and identical
20:51[Music]
20:52twins and some spring to life days after
20:56their siblings have been conceived
20:59[Music]
21:01the embryos transform into
21:04fetuses and with the growth spur comes a
21:07fight for food and
21:09space a 4D look at the Battle brewing in
21:12the
21:13[Music]
21:19womb this is Jennifer a 32-year-old
21:23woman pregnant with
21:26triplets a month ago she released a
21:29single egg which was
21:36fertilized then the egg split in two to
21:39become identical
21:42twins but the story doesn't end there
21:46Jennifer released a second
21:50egg and it too was
21:53fertilized the identicals are joined in
21:56the womb by a third fraternal
21:59creating
22:04triplets this extremely rare process is
22:07known as super fundation meaning extra
22:20fertilization Jennifer's second egg was
22:22fertilized by surviving sperm from the
22:25First Act of intercourse
22:29but this isn't always the
22:32[Music]
22:34case each egg could have been fertilized
22:37by sperm from two different
22:41ejaculates even from two different
22:45[Music]
22:47men for every 400 sets of fraternal one
22:51is made up of twins with different
22:54fathers
23:00the twin triplet and quad embryos have
23:03reached 6 weeks and they're nearly an
23:06inch
23:12long the basic eyeball is 85%
23:17formed and a rudimentary lens takes
23:23shape at this stage the womb can hold
23:27many fetuses the record is 15 although
23:31only nine have ever made it to
23:34birth this scan shows five fetuses at
23:37just a few weeks
23:42old even though Jennifer's triplets were
23:44conceived naturally most higher numbers
23:47of multiple births are a result of
23:49modern fertility treatments
23:58in some cases the woman takes drugs to
24:01stimulate the production of many
24:04eggs and several get fertiliz naturally
24:07through
24:10[Music]
24:12sex in other cases invitro fertilization
24:16or IVF is
24:21used eggs are fertilized outside the
24:23womb in a Petri dish and then two or
24:26more are put back into the
24:35since the Advent of fertility treatment
24:37in the late
24:381970s the number of twins is increased
24:41by
24:4250% the number of triplets and quads has
24:45grown by more than 400%
24:59the twin triplet and quad embryos are
25:02now 8 weeks
25:05[Music]
25:06old nine embryos in all and they're
25:10about an inch in length the size of a
25:13large
25:19grape their eyeballs are now complete
25:23their lenses are almost formed too
25:28but the muscle that allows the eyes to
25:30focus hasn't grown and won't be fully
25:33functional until 6
25:37months in another few weeks the fetuses
25:40will have
25:46eyelids the head one of the earliest and
25:49biggest structures to grow makes up
25:52oneir of the fetus's
25:54[Music]
25:56body as an adult that would be
25:58equivalent to having a head the size of
26:01a grizzly
26:03[Music]
26:06bears at Birth the head will still
26:09account for a quarter of the baby's size
26:13the rest of the body won't catch up till
26:20adolescence the embryos finally resemble
26:23tiny humans and now become known as
26:27fetuses from the Latin word meaning
26:31[Music]
26:42Offspring at 9 weeks their brains are
26:45developing
26:49fast on average 2.5 million new nerve
26:53cells are created every minute
26:59and the number will exceed 100 billion
27:01by
27:07birth now the fetus's body start to
27:16twitch but the movements aren't
27:18controlled by their brains their
27:20involuntary reflex
27:26spasms and they stimulate the growth of
27:28muscles and strengthen
27:37joints their hearts are also picking up
27:42speed after starting 3 weeks into
27:45development at 75 beats per minute they
27:48gradually increase until they reach
27:50their Peak at 9 weeks a frenetic 165
27:55beats per minute
27:59in the latter half of pregnancy they
28:01slow down to 125 to 150
28:07beats a child's heart beats 70 to 110
28:11times a
28:13minute and adults 70 to
28:22[Music]
28:2380 inside the womb the twins triplets
28:27and quads are still unaware of each
28:31other but they're already affecting each
28:36other in all multiple pregnancies the
28:39competition for resources is
28:44fierce for fraternal it's limited
28:47because each twin has its own chonic
28:50sack and
28:51[Music]
28:55placenta but for identicals who share a
28:58coron more often than not an unconscious
29:01battle has
29:04begun each needs the maximum amount of
29:07nutrients it can
29:10extract but there's a limited
29:14[Music]
29:22Supply at Birth one twin usually weighs
29:26more than the other depending on the
29:28efficiency of the
29:34placenta but the differences tend to
29:36even out as the babies grow
29:47up the fetuses are now 10 weeks
29:51old a quarter of the way through
29:53development
29:58until now they've been living in The
30:00Secret World of the human
30:05womb but the mothers are about to get
30:08their first view of the delicate
30:10creatures growing inside
30:12them and the 4D scans will reveal many
30:16surprises in great
30:20detail conjoin twins mirror images and a
30:25strange phenomenon called Vanishing
30:27twins
30:28syndrome you could be a twin and not
30:31even know
30:38it it's week 10 for the twins triplets
30:41and
30:42quads and between now and 14 weeks most
30:47pregnant women usually have their first
30:49ultrasound scan
30:51[Music]
30:58and carrying multiples there's plenty to
31:01see as they interact with each
31:03[Music]
31:08other the pictures are produced by
31:11sending ultra high frequency sound waves
31:14far too high for humans to hear from the
31:17probe into the body of the
31:23[Music]
31:26mother the the sound waves penetrate
31:29soft tissue but bounce off denser
31:32structures like
31:34bone from the pattern of reflected waves
31:37the computer creates an image of the
31:39Hidden
31:45fetus traditionally this would be a
31:47plain two-dimensional
31:50image but new technology presents the
31:53images in
31:543D and sequencing them in time produces
31:58four dimensional
32:01[Music]
32:05scans the scan checks the size and
32:07health of the developing fetus but it
32:10also gives mom a chance to find out if
32:12she's carrying one baby or
32:17more this is baby that should be baby
32:20sick oh my
32:24[Music]
32:26goodness and alter sound scans have
32:28divulged a startling
32:32[Music]
32:34secret many of us traveled our first few
32:36months in the womb with one or more
32:41companions only to have them vanish
32:44before
32:45[Music]
32:48birth this scan taken at 12 weeks shows
32:52two fetuses developing in their mother's
32:54womb
32:56[Music]
32:59but there are three gestational
33:02spaces the one on the right used to
33:05contain a third
33:10fetus 4 weeks ago it was developing just
33:14like the
33:16others but then it just
33:20disappeared slowly shrinking and then
33:22reabsorbing back into the uterine lining
33:29it's called Vanishing twin
33:32[Music]
33:37syndrome scientists think that this is
33:39caused by chromosomal
33:42abnormalities or a lack of adequate
33:44resources from the overworked
33:49placenta nature sacrifices one or more
33:52so the others survive
33:58[Music]
33:59some mothers know they have a Vanishing
34:01twin after seeing it on a scan like this
34:09one others Discover at Birth when it
34:12occasionally shows up as a small piece
34:14of fibrous tissue on the
34:19placenta but many mothers and their
34:22surviving babies will never know it
34:24happened
34:31most of us find it surprising that twins
34:33can
34:37vanish but how often it occurs is even
34:40more
34:43surprising scientists estimate that up
34:46to 21% of fraternal twins lose their
34:52sibling in the case of identicals who
34:55share a placenta the number skyrockets
34:58to
35:0150% some even claim that one in every
35:04eight people may have started Life as a
35:08twin only to have their sibling
35:10disappear while still in the
35:15womb and scientists think they can point
35:18to clues that may indicate which of us
35:20have lost a
35:26twin occasionally
35:28a set of identical twins will be born
35:30known as Mirror Image
35:32twins instead of being identical images
35:35of each other they are mirror
35:38images where one is right-handed the
35:41other is
35:43[Music]
35:45left Mirror Image twins are formed when
35:49the egg splits
35:50late 9 days after
35:54conception when the egg has already
35:56determined its left and right
36:05side in some rare cases even the
36:08internal organs will be
36:11[Music]
36:14mirrored one twin has her heart on the
36:17left the other on the
36:23right put this together with the fact
36:25that left-handedness occurs more
36:27frequently among Twins and the end
36:30result is a startling
36:34Theory some left-handed people may be
36:37the surviving sibling of a vanished
36:45[Music]
36:50twin
36:52identicals fraternal miror images and
36:56super f
36:59each has valuable lessons to teach about
37:01how humans develop and come to
37:04be but one of the most profound lessons
37:07is taught by the most extraordinary type
37:10of
37:10twins siese or conjoin
37:19twins there are two theories about how
37:22conjoin twins
37:25form one is that an egg splits so late
37:28it never fully
37:32separates the other is that it splits
37:35early but somehow the two developing
37:38embryos are drawn back together and
37:44[Music]
37:47fuse the second idea is more
37:50popular and there's intriguing evidence
37:53to support it
37:58every human has adhesion molecules tiny
38:02molecules that act like the velcro of
38:04the
38:06body as organs develop in the womb two
38:10arms two legs a right side and a left
38:13side adhesion molecules pull these two
38:16sides together in a matching and broadly
38:19symmetrical
38:22pattern the molecules are programmed
38:25only to attract their like an arm to an
38:28arm the left side of the face to the
38:30right side and so
38:37on conjoined twins are only joined by
38:40matching
38:42organs head to
38:44head chest to
38:47chest or waist to waste like mere images
38:51of each
38:55other this suggests that the adhesion
38:58molecules in each baby are confusing
39:00their own bodies with their
39:04neighbors and literally fusing the two
39:07embryos
39:08[Music]
39:13together approaching the end of the
39:15first trimester or 3 months the twins
39:19triplets and quads resemble human babies
39:21for the first time
39:23[Music]
39:27and they act in ways that until now were
39:30never seen
39:35before it's Mind Over Matter a new world
39:39of movement kicking and pushing action
39:43and reaction and the race for space
39:51begins at 12 weeks or 3 months the twins
39:55triplets and quads have reached a
39:57milestone in
40:00gestation the embryos have grown from
40:03eggs smaller than grains of sand to
40:06fetuses as big as
40:09fists space in the womb is starting to
40:13shrink and they're starting to look like
40:16human
40:18beings during the first scan at 12 weeks
40:21parents can see the faces of their
40:23babies for the first time that's amazing
40:28[Music]
40:38[Music]
40:40they grow more robust each day and the
40:43risk of miscarriage is low for
40:48most statistically the risks are much
40:51higher for twins that share a placenta
40:55[Music]
41:02it's still too early to tell whether the
41:05fetuses are boys or
41:09girls every fetus has a protuberance in
41:12the genital
41:13area but it doesn't give away their
41:24gender gender identification is is even
41:27tougher when there are multiple fetuses
41:29in the
41:32womb an ultrasound operator can hardly
41:36identify which genitals belong to which
41:50fetuses as for space there's still
41:53plenty of it in the
41:55womb even the quads aren't touching
41:59yet but that's about to
42:03change for multiples the second
42:05trimester is a dramatic time in their
42:08[Music]
42:12development from 3 to 6 months they'll
42:15make their first real
42:21movements no longer the Twitches of the
42:24developing nervous system but the first
42:27signs of recognizable infant
42:34behavior and this Behavior will bring
42:37them into contact with each other for
42:39the very first
42:49time the network of nerves now extends
42:53to most parts of the body
42:58the brain finally controls its own
43:03limbs no one knows why but females tend
43:07to move
43:08first kicking
43:15pushing in the case of single fetuses
43:18these movements meet no
43:23resistance but when two or more siblings
43:25share a wound action leads to
43:31reaction when one kicks the other
43:38flinches when one pushes the others
43:49touch scientists believe this early
43:52pattern of action and reaction seen
43:55clearly in this 4D Al ound of fraternal
43:58twins may be
44:00beneficial it may also play an important
44:03role in accelerating their
44:12development early in the second
44:14trimester the fetuses still aren't
44:17conscious of sharing the limited space
44:19of the womb with their brothers and
44:23sisters but this won't be the case for
44:26long
44:31at 16 weeks a growing fetus moves its
44:34body in increasingly intricate
44:39Maneuvers and it develops an awareness
44:41of its
44:45space here a multiple has an advantage
44:48over a single
44:53fetus this sense proprioception is an
44:57unconscious awareness of the body in
45:04space and it will be essential later in
45:06life as it helps us navigate our
45:12world as adults we take in information
45:15through a variety of
45:18organs eyes ears and
45:22nose building up a mental understanding
45:25of where we are
45:30[Music]
45:33thanks to this understanding we can
45:35coordinate our movements standing
45:37without falling over running and jumping
45:41and avoiding solid
45:47objects this sense of awareness begins
45:49with early movements in the womb as a
45:52fetus explores its environment for the
45:54first time
45:56[Music]
46:07for a single fenus this exploration is
46:10usually limited to the two objects in
46:12his grasp his own body and the umbilical
46:18cord but for twins and higher sets of
46:21multiples it's much busier with much
46:24better variety
46:31for the small number of identical twins
46:34sharing an amniotic sack there are no
46:41[Music]
46:45barriers so they're free to grasp each
46:48other's hands
46:51feet umbilical
46:53cords even each other's faces
47:03but even multiples in separate amniotic
47:05Sachs can easily
47:16interact the amnon is highly
47:21flexible it's also very
47:24thin about two cells thick
47:32when looking on a 4D scan it's almost
47:41invisible but the amneon is extremely
47:46[Music]
47:51tough it stretches and flexes as the
47:54fetus explores its surroundings
48:05[Music]
48:21at 4 and 1/2 months halfway through
48:23gestation the senses are on the verge of
48:26develop ing for the twins triplets and
48:34quads their digestive systems are
48:36gearing
48:39up for now all the nourishment they need
48:42goes from the placenta directly into
48:45their
48:46bloodstream but when they're born
48:48they'll need to be able to swallow and
48:54digest and what better way to get
48:56prepared than to open their mouths and
48:58drink in some of the amniotic fluid that
49:01surrounds
49:02[Music]
49:05them their early efforts are seen in
49:08this 4D
49:13scan flavors from the food that Mom eats
49:16are transferred through the placenta
49:19into the fetus's bloodstream and then
49:21out into the amniotic fluid
49:31[Music]
49:34the fetuses sample it as their taste
49:36buds
49:42develop twins are exposed to the same
49:45flavors in the womb at the same time so
49:48they may have similar tastes in Foods as
49:50they grow up
50:00their senses are developing quickly and
50:02the fetuses are ready to use
50:05[Music]
50:06them Twins and other multiples are known
50:09for a particular characteristic in
50:13utero they transform the womb into a
50:17prenatal playroom here games abound but
50:21not everyone knows how to play nice
50:26it's 20 weeks or five months into
50:31gestation the twins triplets and quads
50:34are about 7 and 1/2 in long small enough
50:38to cradle in their mother's
50:42palm they can't open their eyes yet but
50:45the main structure of the eyeball is
50:49complete the iris which controls the
50:52amount of light that enters the eye is
50:54forming but the pupil do doesn't appear
50:57until closer to
51:05birth the fifth month is a critical time
51:08for the nervous
51:10system the number of nerve cells
51:12increases at a staggering rate 2.5
51:16million neurons per
51:19minute a whopping 100 billion by birth
51:29all they have to do now is
51:33grow but this will also become their
51:36biggest
51:42problem for the past 5 months each has
51:45developed at about the same rate as
51:47single
51:54babies but eventually the womb will run
51:57out of
51:59space it won't be able to house two
52:01full-size
52:05babies so on one hand neither will
52:08benefit from a low birth weight on the
52:11other hand if they get too big they
52:14could trigger premature labor
52:16endangering both twins
52:27gradually their rate of growth starts to
52:29slow
52:35down from this point on the obstetrician
52:39will monitor both the mother and her
52:41fetuses
52:42regularly to ensure that they continue
52:45to grow at an equal
52:48pace and slowly enough for each of their
52:51systems to reach maturity before Labor
52:57[Music]
53:00a woman's womb can support a fetus up to
53:03approximately 12
53:07[Music]
53:09lbs usually single babies are born
53:12between 5 1/2 and 12
53:16lb twins between 4 1/2 and 6 1/2
53:20lb and triplets between 3 and 1/2 and 5
53:24lb
53:28quads and higher multiples are sometimes
53:31born at just 2 lbs each and need weeks
53:34of intensive
53:38care taller women have longer abdomen so
53:42they can carry greater
53:47weight Jennifer carrying the tripet is
53:51nearly 6 ft tall so she has an advantage
53:56is like all the way across her fetuses
54:00will gestate longer which is crucial for
54:02survival outside the womb that's the
54:06one baby a is down here right here in
54:09this area he goes from here to there and
54:11then baby b is from right here to here
54:15and then
54:16baby all the
54:306 months or 24 weeks into
54:34development the lungs start to form
54:36surfactant a greasy substance that helps
54:39babies breathe after they're
54:41born it allows the lungs to separate
54:44while a breath is being
54:51drawn higher multiples are almost always
54:54born prematurely so doctors give moms a
54:57steroid to help surfactant
55:02form the babies have grown so much
55:06they're too big to be shown together in
55:08the field of a 4D
55:13scan but for the first time their
55:16mothers will see their own babies
55:19[Music]
55:22interacting as each baby appears a limb
55:25of one of the others usually pops into
55:32[Music]
55:34frame these 4D scans show one twin
55:38pushing against the
55:42[Music]
55:46other even fraternal twins in their own
55:49corons feel their neighbor moving in on
55:52their space
56:00space is becoming cramped and the twins
56:03and other multiples are about to engage
56:06in a fascinating prenatal developmental
56:09activity game
56:21playing and some of these behaviors
56:23stick around even when the twins are
56:25outside the
56:34womb in one case fraternal twins are
56:37regularly seen in scans cheek to cheek
56:40on each side of the dividing
56:53corons at about one year of age their
56:56favorite game is to stand on either side
56:59of a curtain and laugh as they touch
57:01each other through the
57:08fabric scientists think their prenatal
57:11Behavior carried over into Early
57:21Childhood acts of aggression can carry
57:23over as well twins who behave
57:26aggressively in utero May display
57:29similar behavior in
57:31childhood another case involves a twin
57:33pair at about four months
57:36gestation one twin is dominant and
57:40aggressive the other quiet and more
57:46submissive the first twin has a habit of
57:49pushing and hitting the
57:53other and instead of standing his ground
57:56the second Twin withdraws and places his
57:58head on the placenta as if for Comfort
58:01or
58:06protection when the twins enter the
58:08world and grow up they show the same
58:11relationship
58:14pattern at 4 years old whenever a fight
58:18breaks out the quieter twin retreats to
58:21his bedroom and puts his head on the
58:22pillow
58:33these fraternal twins are positioned
58:35head to toe and look like they're
58:39fighting the 4D scan captures one of the
58:42twins kicking the other's
58:50head but these movements probably aren't
58:53as aggressive as they seem
58:59it could just be a consequence of their
59:07positions the twin on the left might be
59:10kicking to exercise his
59:16leg while the twin on the right is
59:18learning an early invaluable life
59:22lesson using his hands to protect his
59:25face from a
59:36salt twins are a reproductive
59:42accident but single egg identicals
59:45provide an opportunity for scientists to
59:48understand how
59:50personalities skills even intelligence
59:53develops
59:59and it's an eye openening
1:00:02experience delve into the world of
1:00:04fraternal and identicals where
1:00:06unexpected similarities and surprising
1:00:09differences come to
1:00:12light just over 6 months into gestation
1:00:16the twins triplets and quads open their
1:00:18eyes in the womb separating the eyelids
1:00:21for the first
1:00:23time some scientists believe believe the
1:00:26babies can see now and the first thing
1:00:29they catch sight of is each other in the
1:00:33darkness for single babies the view is
1:00:36limited but for twins there's a lot to
1:00:39take in when light shines through the
1:00:44womb the inner and middle ear growing
1:00:47since week four are now fully formed and
1:00:54functional the Fe is can hear their
1:00:57mother's heartbeat and the rushing
1:00:59sounds of amniotic
1:01:05fluid they can also hear muffled sounds
1:01:08from the outside world including music
1:01:11and
1:01:14voices twins are now a quarter of their
1:01:17birth weight while triplets and quads
1:01:20are a
1:01:22third their brains are still developing
1:01:25r
1:01:29rapidly by birth the neural circuits
1:01:32will be comprised of 100 trillion
1:01:38synapses each twin is very similar and
1:01:42yet also very
1:01:46different and the differences will
1:01:48affect both looks and personality
1:01:52[Music]
1:01:59it's hard to tell how or where these
1:02:02similarities and differences
1:02:08originate obviously the most striking
1:02:11similarities come from their shared
1:02:13[Music]
1:02:18genes single legegg twins have almost
1:02:21identical bodies and almost identical
1:02:23brains
1:02:25[Music]
1:02:29these scans show patterns on the brains
1:02:31of a pair of fraternal
1:02:35twins these brains belong to a pair of
1:02:38identicals which are much more
1:02:48similar so it should come as no surprise
1:02:51that as identicals grow up they tend to
1:02:53share views about subjects as diverse as
1:02:56Modern Art and the death
1:03:06penalty identicals also have closer IQs
1:03:10than
1:03:13fraternal and show similar
1:03:15susceptibilities to anger stress
1:03:18thrill-seeking and
1:03:23happiness but not every major
1:03:26characteristic of twins is
1:03:33inherited scientists think that the
1:03:35environment in the womb can have an
1:03:38effect and sometimes a dramatic
1:03:42[Music]
1:03:45one fraternal twins who derive from two
1:03:48eggs share half their
1:03:53genes their IQs are often
1:03:57different but new research is also
1:03:59finding subtle variations in the IQs of
1:04:10identicals this may seem strange because
1:04:13identicals are nearly exact replicas of
1:04:15each other and usually make the long
1:04:17journey through gestation in close
1:04:19proximity
1:04:31most identical twins share a single
1:04:33coron therefore sharing a single food
1:04:36and oxygen
1:04:39[Music]
1:04:42source but as we've seen 30% of
1:04:45identicals split early enough after
1:04:47conception to acquire their own coron
1:04:50and with it their own placenta
1:04:57[Music]
1:05:00studies show that the IQs of twins with
1:05:03separate placentas are more likely to
1:05:05vary than the IQs of twins who share
1:05:15one the minor differences in the quality
1:05:18and degree of food and oxygen they
1:05:20receive modify their brains and mental
1:05:23abilities
1:05:27[Music]
1:05:32sharing a placenta can also lead to
1:05:34complications if one twin restricts the
1:05:37blood flow to the
1:05:41other advances in fetal surgery mean
1:05:44that doctors can now treat this
1:05:46condition using Laser Technology in the
1:05:51womb the wonders of modern science and
1:05:55the rich Risky Business of multiple
1:05:57births from deadly Tangles to lethal
1:06:00transfusions the womb can be a dangerous
1:06:11place 28 weeks or 7 months into
1:06:15development there's a new risk to the
1:06:17twins triplets and
1:06:20quads doctors are paying close attention
1:06:23to the umbilical cord
1:06:28this masterpiece of natural design is
1:06:31thick and resilient but it can also be
1:06:34[Music]
1:06:35dangerous it contains two arteries and a
1:06:38vein that coil around each other but
1:06:41somehow manage to keep from getting
1:06:42knotted or
1:06:47kinked even if the umbilical cord wraps
1:06:50around the baby's neck it still delivers
1:06:53vital nutrients
1:06:58but for twins sharing an amniotic sack
1:07:01this lifegiving supply line presents a
1:07:03unique
1:07:07danger identicals can get entangled in
1:07:10each other's cords cutting off the flow
1:07:12of food and oxygen to themselves or to
1:07:15their
1:07:19twin this 4D scan shows just how
1:07:23precarious the situation can get
1:07:26[Music]
1:07:33to help reduce the risk of entanglement
1:07:36identicals who share a single amniotic
1:07:38sack are often delivered by
1:07:42[Music]
1:07:53cesarian in the last week weeks before
1:07:56birth the babies put on as much weight
1:07:58as they
1:08:01can the larger and stronger they are the
1:08:10better at 7 months Julie's quads now
1:08:14weigh between 1 and 2 lb close to their
1:08:17predicted birth weight
1:08:27[Music]
1:08:28and one of the things doctors watch out
1:08:30for is twint Twin transfusion
1:08:38syndrome ideally they all develop at
1:08:41about the same
1:08:42Pace with all of them gaining the same
1:08:45amount of weight
1:08:49[Music]
1:08:56but identicals like Jules are like trees
1:08:59growing from the same
1:09:01Roots they all harmlessly exchange blood
1:09:04across their shared
1:09:14placenta for 5 to 38% of monozygotic
1:09:18twins circulation between them becomes
1:09:23unbalanced one gets too much much blood
1:09:26which can overload the cardiovascular
1:09:28system and cause death from heart
1:09:31[Music]
1:09:36failure the other doesn't get enough and
1:09:39may die from severe
1:09:42[Music]
1:09:47anemia there are several complex reasons
1:09:50why this
1:09:51happens but it's not hereditary or
1:09:54genetic
1:09:56normally it occurs between 15 and 28
1:09:59weeks of gestation the middle months of
1:10:06pregnancy but it can be treated the
1:10:09blood supply is cut off from one twin to
1:10:12the other using an endoscopic
1:10:19laser before this procedure twins with
1:10:22this rare condition faced a 20% chance
1:10:25of of
1:10:26survival now it's between 65 and
1:10:3270% from the hazards of an overly
1:10:35crowded womb to the ultimate in
1:10:37high-risk deliveries Jennifer's triplets
1:10:40are about to Glimpse their first view of
1:10:43the outside
1:10:50world birth is just around the corner
1:10:53for the twins triplets in ODS and
1:10:56doctors monitor their health
1:10:59closely but the fetuses are also
1:11:01regulating and controlling their
1:11:03development at least to some
1:11:07degree if one twin isn't receiving
1:11:10enough blood in the womb his body takes
1:11:13steps to preserve his
1:11:18brain he's able to regulate the volume
1:11:21of blood that different parts of his
1:11:23body receive
1:11:27only a limited amount pumps to his
1:11:29extremities which need it
1:11:31less and more flows to his brain to keep
1:11:35it from starving and suffering
1:11:41damage it's a miracle of fetal
1:11:44biology and even when babies grow up the
1:11:48legacy of this process lives
1:11:52on but look to the fingertips for it not
1:11:55the
1:11:58[Music]
1:11:59brain as fingertips develop they receive
1:12:02blood from the
1:12:05veins this makes them swell and
1:12:08distinctive patterns called whirls
1:12:12form they're most obvious on the right
1:12:14index
1:12:18finger the fingers on the left hand
1:12:21share the same blood supply as the legs
1:12:27if blood is directed away from the legs
1:12:29and other extremities during development
1:12:32there are fewer whirls on the left index
1:12:36[Music]
1:12:38finger these patterns can help indicate
1:12:41how healthy the heart will be later in
1:12:43life
1:13:02at 30 weeks or 7 and 1/2 months
1:13:06everything is in place as it should be
1:13:08for the twins triplets and
1:13:12quads they have intricate features like
1:13:18eyelashes for single babies this final
1:13:2110-week period is about one thing
1:13:24growing
1:13:32but for multiples it's not so easy space
1:13:35has run out in the
1:13:40womb the babies push and shove as they
1:13:43compete for Elbow
1:13:49Room their eyeballs move in their
1:13:51sockets and react to light
1:14:01when a strong light shines on the
1:14:03abdomen the babies react to
1:14:20it 32
1:14:22weeks single babies are still about
1:14:25eight weeks from
1:14:26birth but for the triplets the big
1:14:29moment is much
1:14:33closer all multiples present a medical
1:14:38challenge a delicate balance between
1:14:41leaving them inside long enough to be
1:14:43sufficiently large at
1:14:45Birth but not so long that they endanger
1:14:49their mother or
1:14:53themselves their l
1:14:55have to be mature enough to breathe on
1:14:57their
1:15:02own 34 weeks in the womb is ideal for
1:15:06triplets even though it's 6 weeks before
1:15:09full
1:15:11term because of the dangers of natural
1:15:14labor doctors recommend a
1:15:22cesarian for the past eight months
1:15:25Jennifer's triplets have had no one but
1:15:27each other for
1:15:30companionship they were conceived
1:15:33together they've grown and fed side by
1:15:37side they've heard the same sounds and
1:15:41seen the same
1:15:45sights now they're about to leave their
1:15:49cozy world and face the cold lights of
1:15:51the operating room
1:15:58they'll also meet their mother for the
1:16:00very first
1:16:02[Music]
1:16:13time in Jennifer's case doctors opt for
1:16:1632 weeks instead of 34
1:16:27she's given a local
1:16:31anesthetic with no pain in her abdomen
1:16:34she'll be conscious the entire
1:16:39[Music]
1:16:43time the surgeon prepares to make the
1:16:46first
1:16:49incision inside the babies have no idea
1:16:53what's coming
1:16:59doctors always perform cesarians quickly
1:17:03to reduce the risk of
1:17:08complications the first baby is out it's
1:17:12one of the identicals a
1:17:14boy he takes his first breath and lets
1:17:17loose a healthy
1:17:20Scream the cord to the placenta which
1:17:23has been his lifeline for 8 months is
1:17:26finally
1:17:29cut the surgeon looks for his identical
1:17:32brother who is in the same cionic
1:17:39sack he's out quickly
1:17:44too but finding the final fraternal
1:17:47brother who's in his own chonic sack is
1:17:51a challenge
1:18:07but finally he emerges too feet
1:18:14first me the three babies are fit and
1:18:18healthy despite the cramped living
1:18:21conditions of the past few months
1:18:28they weigh just over 4 and2 lbs
1:18:32each
1:18:34209
1:18:36[Music]
1:18:384. but they're 8 weeks
1:18:43premature so high-tech incubators that
1:18:46imitate the world of the womb will help
1:18:48them gain weight and bring their lungs
1:18:51to maturity
1:18:57in developing countries multiples are
1:19:00placed together for warmth and
1:19:06comfort at 38 weeks it's time for the
1:19:10twins to be
1:19:13born about half of twins are delivered
1:19:16by
1:19:17cesarian which many mothers prefer to a
1:19:20natural
1:19:22[Music]
1:19:23birth but Rachel's given birth before
1:19:27and it's up to her how her twins come
1:19:29into the
1:19:34world a tangled cord and a life hangs in
1:19:38the balance but the riskiest delivery of
1:19:41all is still to
1:19:42[Music]
1:19:53come and 38 weeks Rachel's twins are
1:19:57about to be
1:20:00born but unlike single babies they'll be
1:20:03entering the world a full week early due
1:20:06to cramped
1:20:09quarters their lungs are robust and
1:20:11their bodies are
1:20:16ready twins normally weigh just over 4
1:20:20lbs each when they're born
1:20:22[Music]
1:20:25their smaller bodies make them good
1:20:27candidates for a natural
1:20:30birth which is what Rachel
1:20:34wants she's had two children like this
1:20:36before and she's capable and confident
1:20:40that things will go
1:20:43smoothly a combination of hormones
1:20:45triggers labor and a baby normally turns
1:20:49head down as the pregnancy comes to
1:20:52term but with two in the womb
1:20:55this isn't so
1:21:01[Music]
1:21:05easy the baby positioned closest to the
1:21:08head of the birth canal is
1:21:11[Music]
1:21:14first the amniotic Waters have
1:21:17[Music]
1:21:20broken and the baby's head pushes
1:21:22through the remnants of the sack that
1:21:24protected it for nearly 9
1:21:32months the cervix is fully dilated and
1:21:35the muscles of the uterus continue to
1:21:37move the baby toward the outside world
1:21:54Rachel has been pushing for 3
1:21:57[Music]
1:22:06hours the first baby starts to
1:22:12emerge and eventually he enters the
1:22:15world
1:22:16[Music]
1:22:20completely the cords are entangled but
1:22:23it's pretty common with multiples and
1:22:26the Midwife unwraps it with
1:22:36ease it's a boy weighing more than 6
1:22:39and2 lb
1:22:47[Music]
1:22:58for the first time in 9 months this baby
1:23:01has the womb all to
1:23:04herself but it's a short-lived
1:23:08[Music]
1:23:13[Music]
1:23:19Independence 10 minutes after the first
1:23:22birth the second baby's head of
1:23:27appears she is and she follows her
1:23:30brother into the outside
1:23:35world it's a girl weighing just under 6
1:23:41[Music]
1:23:43lb after being separated for a few
1:23:46minutes the fraternal twins are
1:23:52reunited but the mother of the quads
1:23:55faces the most intensive
1:23:58birth she conceived her babies on a 1 in
1:24:0164 million chance and they've been in
1:24:04the womb for only 7 months 2 months less
1:24:08than single
1:24:10babies each weighs only 2 lb a quarter
1:24:14of the weight of an average
1:24:16baby if each had the womb to themselves
1:24:19they would remain here much
1:24:21longer but space has become impossible
1:24:25tight until the mid 1970s quads were
1:24:29usually born naturally but today a large
1:24:33medical team awaits
1:24:36them and the stakes are high when these
1:24:40four babies exit the womb they'll face
1:24:42the ultimate
1:24:44Challenge survival looking for a bigger
1:24:47house on TV yeah with Optimum homes you
1:24:49can look at houses right on your TV
1:24:51pretty cool but we don't need a bigger
1:24:53house
1:24:54I'll tell you my mom may be moving
1:24:58in give me that how about this
1:25:04one this one detached garage with an
1:25:07upstairs apartment it's not heated is
1:25:09heat important introducing Optimum homes
1:25:12find your next home without leaving home
1:25:15treat me with
1:25:22understanding the quads have reached
1:25:24reached 29 weeks and 3
1:25:27days it's time to operate before it gets
1:25:30too
1:25:33risky with a large number of medical
1:25:35staff on hand the focus is on the mother
1:25:38and the impending
1:25:43birth the surgeon cuts through the
1:25:45abdomen to locate the first
1:25:52baby each has its own inner amniotic
1:26:07sack cutting through the first
1:26:10amnon the baby is out
1:26:17Quickly's
1:26:22day it's a girl weighing in at 2
1:26:34lb she's followed by the second baby
1:26:37another girl who is just as
1:26:44small the team checks each baby's vital
1:26:47signs to make sure they can breathe on
1:26:49their own
1:26:53[Music]
1:27:02these four babies are being born almost
1:27:0411 weeks
1:27:12early the doctor grabs the third smaller
1:27:18baby he removes it from the uterus and
1:27:21it's taken for examination by the
1:27:23midwife
1:27:27my
1:27:37beautiful with only one baby left this
1:27:41extraordinary quadruplet pregnancy is
1:27:44almost over
1:28:00the fourth baby is finally
1:28:03delivered four little girls in
1:28:07[Music]
1:28:13all incredibly they all weigh about 2 lb
1:28:17each a quar of the average 8 lbs for
1:28:21newborns Beau beautiful they'll all
1:28:25spend several weeks in incubators before
1:28:27heading
1:28:29[Music]
1:28:43home Rachel's twins are 8 weeks old but
1:28:47have been growing together for almost a
1:28:50year they're starting to develop their
1:28:53own personality
1:28:56ities and even though they're fraternal
1:28:58rather than identical twins they're
1:29:01still pretty similar influenced by their
1:29:04genes and their shared time in the
1:29:08[Music]
1:29:10womb identicals will be much more
1:29:13similar due to their close
1:29:15genetics but their upbringing will also
1:29:18play A Part
1:29:26Jennifer's triplets are home from the
1:29:28hospital all breathing peacefully on
1:29:31their
1:29:32own they all seem similar now but as
1:29:36they grow up the fraternal twin is more
1:29:39likely to strike out on his own than the
1:29:41two
1:29:46[Music]
1:29:48identicals Julie's quads are now 3
1:29:51months old and putting on weight f fast
1:29:55despite being born at only 2 lb
1:30:00each they're fed a special milk formula
1:30:03loaded with calories to speed up their
1:30:09growth it's taken three months for the
1:30:11four of them to reach the average birth
1:30:13weight of 8
1:30:18lb even today with modern medical
1:30:22advances multiple births are
1:30:24reproductive
1:30:27Miracles they only account for a small
1:30:30percentage of human births but they hold
1:30:33a Fascination for
1:30:37many they are a challenge for Science
1:30:40and a window on reproduction giving
1:30:42greater insights into the remarkable
1:30:45world within the
1:30:50womb and for the twins triplets and
1:30:53quads
1:30:55these early interactions with their
1:30:57brothers and sisters in the womb will
1:30:59connect and Define them as they grow up
1:31:03and provide a source of comfort and
1:31:05inspiration to each other throughout
1:31:08their lives