0:00:06.645,0:00:09.047
In 1978, Louise Brown became [br]

0:00:09.047,0:00:14.450
the world's first baby to be born[br]by in vitro fertilization, or IVF.

0:00:14.450,0:00:17.780
Her birth revolutionized [br]the field of reproductive medicine.

0:00:17.780,0:00:20.931
Given that approximately one in eight[br]heterosexual couples

0:00:20.931,0:00:22.997
has difficulty conceiving,

0:00:22.997,0:00:25.172
and that homosexual couples[br]and single parents

0:00:25.172,0:00:27.804
often need clinical help to make a baby,

0:00:27.804,0:00:30.561
the demand for IVF has been growing.

0:00:30.561,0:00:36.889
IVF is so common, that more than 5 million[br]babies have been born through this technology.

0:00:36.889,0:00:42.645
IVF works by mimicking the brilliant[br]design of sexual reproduction.

0:00:42.645,0:00:44.789
In order to understand IVF,

0:00:44.789,0:00:49.516
we first need to take a look [br]at the natural process of baby making.

0:00:49.516,0:00:53.788
Believe it or not, [br]it all starts in the brain.

0:00:53.788,0:00:57.127
Roughly fifteen days [br]before fertilization can happen,

0:00:57.127,0:01:02.612
the anterior pituitary gland secretes[br]follicle stimulating hormone, FSH,

0:01:02.612,0:01:05.476
which ripens a handful [br]of follicles of the ovary

0:01:05.476,0:01:07.817
that then release estrogen.

0:01:07.817,0:01:09.788
Each follicle contains one egg,

0:01:09.788,0:01:14.340
and on average, [br]only one follicle becomes fully mature.

0:01:14.340,0:01:17.295
As it grows and continues [br]to release estrogen,

0:01:17.295,0:01:21.664
this hormone not only helps coordinate[br]growth and preparation of the uterus,

0:01:21.664,0:01:27.088
it also communicates to the brain[br]how well the follicle is developing.

0:01:27.088,0:01:29.466
When the estrogen level is high enough,

0:01:29.466,0:01:35.378
the anterior pituitary releases a surge[br]of luteinizing hormone, LH,

0:01:35.378,0:01:37.213
which triggers ovulation

0:01:37.213,0:01:42.417
and causes the follicle to rupture[br]and release the egg.

0:01:42.417,0:01:44.468
Once the egg leaves the ovary,

0:01:44.468,0:01:49.179
it is directed into the Fallopian tube[br]by the finger-like fimbriae.

0:01:49.179,0:01:52.681
If the egg is not fertilized [br]by sperm within 24 hours,

0:01:52.681,0:01:54.807
the unfertilized egg will die,

0:01:54.807,0:01:57.266
and the entire system will reset itself,

0:01:57.266,0:02:02.087
preparing to create a new egg[br]and uterine lining the following month.

0:02:02.087,0:02:05.011
The egg is the largest cell in the body

0:02:05.011,0:02:08.473
and is protected by a thick, [br]extracellular shell of sugar

0:02:08.473,0:02:12.325
and protein called the zona pellucida.

0:02:12.325,0:02:16.576
The zona thwarts the entry and fusion[br]of more than one sperm,

0:02:16.576,0:02:19.978
the smallest cell in the body.

0:02:19.978,0:02:23.060
It takes a man two to three months[br]to make sperm,

0:02:23.060,0:02:26.220
and the process constantly renews.

0:02:26.220,0:02:31.856
Each ejaculation during sexual intercourse[br]releases more than 100 million sperm.

0:02:31.856,0:02:37.035
But only 100 or so will ultimately[br]make it to the proximity of the egg,

0:02:37.035,0:02:43.232
and only one will successfully penetrate[br]through the armor of the zona pellucida.

0:02:43.232,0:02:45.514
Upon successful fertilization,

0:02:45.514,0:02:48.756
the zygote immediately begins [br]developing into an embryo,

0:02:48.756,0:02:52.006
and takes about three days[br]to reach the uterus.

0:02:52.006,0:02:54.282
There, it requires [br]another three or so days

0:02:54.282,0:02:59.742
to implant firmly into the endometrium,[br]the inner lining of the uterus.

0:02:59.742,0:03:02.895
Once implanted, the cells that [br]are to become the placenta

0:03:02.895,0:03:06.037
secrete a hormone that signals[br]to the ovulated follicle

0:03:06.037,0:03:08.898
that there is a pregnancy in the uterus.

0:03:08.898,0:03:12.403
This helps rescue that follicle,[br]now called the corpus luteum,

0:03:12.403,0:03:17.697
from degenerating as it normally would[br]do in that stage of the menstrual cycle.

0:03:17.697,0:03:20.839
The corpus luteum is responsible[br]for producing the progesterone

0:03:20.839,0:03:25.594
required to maintain the pregnancy[br]until six to seven weeks of gestation,

0:03:25.594,0:03:28.273
when the placenta develops[br]and takes over,

0:03:28.273,0:03:32.213
until the baby is born [br]approximately 40 weeks later.

0:03:32.213,0:03:35.587
Now, how do you make a baby in a lab?

0:03:35.587,0:03:37.926
In patients undergoing IVF,

0:03:37.926,0:03:42.333
FSH is administered at levels[br]that are higher than naturally occuring

0:03:42.333,0:03:45.859
to cause a controlled [br]overstimulation of the ovaries

0:03:45.859,0:03:49.599
so that they ultimately [br]produce multiple eggs.

0:03:49.599,0:03:53.462
The eggs are then retrieved [br]just before ovulation would occur,

0:03:53.462,0:03:55.738
while the woman is under anesthesia,

0:03:55.738,0:04:00.111
through an aspirating needle[br]that is guided by ultrasound.

0:04:00.111,0:04:05.029
Most sperm samples are produced[br]by masturbation.

0:04:05.029,0:04:09.599
In the laboratory, the identified eggs[br]are stripped of surrounding cells

0:04:09.599,0:04:13.594
and prepared for fertilization [br]in a petri dish.

0:04:13.594,0:04:16.851
Fertilization can occur [br]by one of two techniques.

0:04:16.851,0:04:20.307
In the first, the eggs are incubated[br]with thousands of sperm

0:04:20.307,0:04:24.725
and fertilization occurs naturally[br]over a few hours.

0:04:24.725,0:04:27.835
The second technique maximizes[br]certainty of fertilization

0:04:27.835,0:04:32.465
by using a needle [br]to place a single sperm inside the egg.

0:04:32.465,0:04:37.181
This is particularly useful when there is[br]a problem with the quality of the sperm.

0:04:37.181,0:04:41.819
After fertilization, embryos can be [br]further screened for genetic suitability,

0:04:41.819,0:04:44.480
frozen for later attempted pregnancies,

0:04:44.480,0:04:48.687
or delivered into the woman's uterus[br]via catheter.

0:04:48.687,0:04:53.913
Common convention is to transfer[br]the embryo three days after fertilization,

0:04:53.913,0:04:56.542
when the embryo has eight cells,

0:04:56.542,0:05:01.137
or on day five, when[br]the embryo is called a blastocyst,

0:05:01.137,0:05:03.769
and has hundreds of cells.

0:05:03.769,0:05:08.717
If the woman's eggs are of poor quality[br]due to age or toxic exposures,

0:05:08.717,0:05:11.478
or have been removed due to cancer,

0:05:11.478,0:05:14.237
donor eggs may be used.

0:05:14.237,0:05:18.671
In the case that the intended mother[br]has a problematic uterus, or lacks one,

0:05:18.671,0:05:22.622
another woman, called [br]the gestational carrier or surrogate,

0:05:22.622,0:05:26.448
can use her uterus to carry the pregnancy.

0:05:26.448,0:05:28.378
To increase the odds of success,

0:05:28.378,0:05:32.330
which are as high as 40%[br]for a woman younger than 35,

0:05:32.330,0:05:36.536
doctors sometimes transfer[br]multiple embryos at once,

0:05:36.536,0:05:39.512
which is why IVF results [br]in twins and triplets

0:05:39.512,0:05:43.050
more often than natural pregnancies.

0:05:43.050,0:05:48.003
However, most clinics seek to minimize[br]the chances of multiple pregnancies,

0:05:48.003,0:05:51.726
as they are riskier [br]for mothers and babies.

0:05:51.726,0:05:56.336
Millions of babies, like Louise Brown,[br]have been born from IVF

0:05:56.336,0:05:59.501
and have had normal, healthy lives.

0:05:59.501,0:06:02.728
The long-term health consequences[br]of ovarian stimulation

0:06:02.728,0:06:05.879
with IVF medicines are less clear,

0:06:05.879,0:06:09.920
though so far, IVF seems safe for women.

0:06:09.920,0:06:11.876
Because of better genetic testing,

0:06:11.876,0:06:13.714
delayed childbearing, [br]

0:06:13.714,0:06:16.765
increased accessibility[br]and diminishing cost,

0:06:16.765,0:06:22.582
it's not inconceivable that artificial[br]baby making via IVF and related techniques

0:06:22.582,0:06:26.717
could outpace natural reproduction[br]in years to come.