[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:06.64,0:00:09.05,Default,,0000,0000,0000,,In 1978, Louise Brown became \N
Dialogue: 0,0:00:09.05,0:00:14.45,Default,,0000,0000,0000,,the world's first baby to be born\Nby in vitro fertilization, or IVF.
Dialogue: 0,0:00:14.45,0:00:17.78,Default,,0000,0000,0000,,Her birth revolutionized \Nthe field of reproductive medicine.
Dialogue: 0,0:00:17.78,0:00:20.93,Default,,0000,0000,0000,,Given that approximately one in eight\Nheterosexual couples
Dialogue: 0,0:00:20.93,0:00:22.100,Default,,0000,0000,0000,,has difficulty conceiving,
Dialogue: 0,0:00:22.100,0:00:25.17,Default,,0000,0000,0000,,and that homosexual couples\Nand single parents
Dialogue: 0,0:00:25.17,0:00:27.80,Default,,0000,0000,0000,,often need clinical help to make a baby,
Dialogue: 0,0:00:27.80,0:00:30.56,Default,,0000,0000,0000,,the demand for IVF has been growing.
Dialogue: 0,0:00:30.56,0:00:36.89,Default,,0000,0000,0000,,IVF is so common, that more than 5 million\Nbabies have been born through this technology.
Dialogue: 0,0:00:36.89,0:00:42.64,Default,,0000,0000,0000,,IVF works by mimicking the brilliant\Ndesign of sexual reproduction.
Dialogue: 0,0:00:42.64,0:00:44.79,Default,,0000,0000,0000,,In order to understand IVF,
Dialogue: 0,0:00:44.79,0:00:49.52,Default,,0000,0000,0000,,we first need to take a look \Nat the natural process of baby making.
Dialogue: 0,0:00:49.52,0:00:53.79,Default,,0000,0000,0000,,Believe it or not, \Nit all starts in the brain.
Dialogue: 0,0:00:53.79,0:00:57.13,Default,,0000,0000,0000,,Roughly fifteen days \Nbefore fertilization can happen,
Dialogue: 0,0:00:57.13,0:01:02.61,Default,,0000,0000,0000,,the anterior pituitary gland secretes\Nfollicle stimulating hormone, FSH,
Dialogue: 0,0:01:02.61,0:01:05.48,Default,,0000,0000,0000,,which ripens a handful \Nof follicles of the ovary
Dialogue: 0,0:01:05.48,0:01:07.82,Default,,0000,0000,0000,,that then release estrogen.
Dialogue: 0,0:01:07.82,0:01:09.79,Default,,0000,0000,0000,,Each follicle contains one egg,
Dialogue: 0,0:01:09.79,0:01:14.34,Default,,0000,0000,0000,,and on average, \Nonly one follicle becomes fully mature.
Dialogue: 0,0:01:14.34,0:01:17.30,Default,,0000,0000,0000,,As it grows and continues \Nto release estrogen,
Dialogue: 0,0:01:17.30,0:01:21.66,Default,,0000,0000,0000,,this hormone not only helps coordinate\Ngrowth and preparation of the uterus,
Dialogue: 0,0:01:21.66,0:01:27.09,Default,,0000,0000,0000,,it also communicates to the brain\Nhow well the follicle is developing.
Dialogue: 0,0:01:27.09,0:01:29.47,Default,,0000,0000,0000,,When the estrogen level is high enough,
Dialogue: 0,0:01:29.47,0:01:35.38,Default,,0000,0000,0000,,the anterior pituitary releases a surge\Nof luteinizing hormone, LH,
Dialogue: 0,0:01:35.38,0:01:37.21,Default,,0000,0000,0000,,which triggers ovulation
Dialogue: 0,0:01:37.21,0:01:42.42,Default,,0000,0000,0000,,and causes the follicle to rupture\Nand release the egg.
Dialogue: 0,0:01:42.42,0:01:44.47,Default,,0000,0000,0000,,Once the egg leaves the ovary,
Dialogue: 0,0:01:44.47,0:01:49.18,Default,,0000,0000,0000,,it is directed into the Fallopian tube\Nby the finger-like fimbriae.
Dialogue: 0,0:01:49.18,0:01:52.68,Default,,0000,0000,0000,,If the egg is not fertilized \Nby sperm within 24 hours,
Dialogue: 0,0:01:52.68,0:01:54.81,Default,,0000,0000,0000,,the unfertilized egg will die,
Dialogue: 0,0:01:54.81,0:01:57.27,Default,,0000,0000,0000,,and the entire system will reset itself,
Dialogue: 0,0:01:57.27,0:02:02.09,Default,,0000,0000,0000,,preparing to create a new egg\Nand uterine lining the following month.
Dialogue: 0,0:02:02.09,0:02:05.01,Default,,0000,0000,0000,,The egg is the largest cell in the body
Dialogue: 0,0:02:05.01,0:02:08.47,Default,,0000,0000,0000,,and is protected by a thick, \Nextracellular shell of sugar
Dialogue: 0,0:02:08.47,0:02:12.32,Default,,0000,0000,0000,,and protein called the zona pellucida.
Dialogue: 0,0:02:12.32,0:02:16.58,Default,,0000,0000,0000,,The zona thwarts the entry and fusion\Nof more than one sperm,
Dialogue: 0,0:02:16.58,0:02:19.98,Default,,0000,0000,0000,,the smallest cell in the body.
Dialogue: 0,0:02:19.98,0:02:23.06,Default,,0000,0000,0000,,It takes a man two to three months\Nto make sperm,
Dialogue: 0,0:02:23.06,0:02:26.22,Default,,0000,0000,0000,,and the process constantly renews.
Dialogue: 0,0:02:26.22,0:02:31.86,Default,,0000,0000,0000,,Each ejaculation during sexual intercourse\Nreleases more than 100 million sperm.
Dialogue: 0,0:02:31.86,0:02:37.04,Default,,0000,0000,0000,,But only 100 or so will ultimately\Nmake it to the proximity of the egg,
Dialogue: 0,0:02:37.04,0:02:43.23,Default,,0000,0000,0000,,and only one will successfully penetrate\Nthrough the armor of the zona pellucida.
Dialogue: 0,0:02:43.23,0:02:45.51,Default,,0000,0000,0000,,Upon successful fertilization,
Dialogue: 0,0:02:45.51,0:02:48.76,Default,,0000,0000,0000,,the zygote immediately begins \Ndeveloping into an embryo,
Dialogue: 0,0:02:48.76,0:02:52.01,Default,,0000,0000,0000,,and takes about three days\Nto reach the uterus.
Dialogue: 0,0:02:52.01,0:02:54.28,Default,,0000,0000,0000,,There, it requires \Nanother three or so days
Dialogue: 0,0:02:54.28,0:02:59.74,Default,,0000,0000,0000,,to implant firmly into the endometrium,\Nthe inner lining of the uterus.
Dialogue: 0,0:02:59.74,0:03:02.90,Default,,0000,0000,0000,,Once implanted, the cells that \Nare to become the placenta
Dialogue: 0,0:03:02.90,0:03:06.04,Default,,0000,0000,0000,,secrete a hormone that signals\Nto the ovulated follicle
Dialogue: 0,0:03:06.04,0:03:08.90,Default,,0000,0000,0000,,that there is a pregnancy in the uterus.
Dialogue: 0,0:03:08.90,0:03:12.40,Default,,0000,0000,0000,,This helps rescue that follicle,\Nnow called the corpus luteum,
Dialogue: 0,0:03:12.40,0:03:17.70,Default,,0000,0000,0000,,from degenerating as it normally would\Ndo in that stage of the menstrual cycle.
Dialogue: 0,0:03:17.70,0:03:20.84,Default,,0000,0000,0000,,The corpus luteum is responsible\Nfor producing the progesterone
Dialogue: 0,0:03:20.84,0:03:25.59,Default,,0000,0000,0000,,required to maintain the pregnancy\Nuntil six to seven weeks of gestation,
Dialogue: 0,0:03:25.59,0:03:28.27,Default,,0000,0000,0000,,when the placenta develops\Nand takes over,
Dialogue: 0,0:03:28.27,0:03:32.21,Default,,0000,0000,0000,,until the baby is born \Napproximately 40 weeks later.
Dialogue: 0,0:03:32.21,0:03:35.59,Default,,0000,0000,0000,,Now, how do you make a baby in a lab?
Dialogue: 0,0:03:35.59,0:03:37.93,Default,,0000,0000,0000,,In patients undergoing IVF,
Dialogue: 0,0:03:37.93,0:03:42.33,Default,,0000,0000,0000,,FSH is administered at levels\Nthat are higher than naturally occuring
Dialogue: 0,0:03:42.33,0:03:45.86,Default,,0000,0000,0000,,to cause a controlled \Noverstimulation of the ovaries
Dialogue: 0,0:03:45.86,0:03:49.60,Default,,0000,0000,0000,,so that they ultimately \Nproduce multiple eggs.
Dialogue: 0,0:03:49.60,0:03:53.46,Default,,0000,0000,0000,,The eggs are then retrieved \Njust before ovulation would occur,
Dialogue: 0,0:03:53.46,0:03:55.74,Default,,0000,0000,0000,,while the woman is under anesthesia,
Dialogue: 0,0:03:55.74,0:04:00.11,Default,,0000,0000,0000,,through an aspirating needle\Nthat is guided by ultrasound.
Dialogue: 0,0:04:00.11,0:04:05.03,Default,,0000,0000,0000,,Most sperm samples are produced\Nby masturbation.
Dialogue: 0,0:04:05.03,0:04:09.60,Default,,0000,0000,0000,,In the laboratory, the identified eggs\Nare stripped of surrounding cells
Dialogue: 0,0:04:09.60,0:04:13.59,Default,,0000,0000,0000,,and prepared for fertilization \Nin a petri dish.
Dialogue: 0,0:04:13.59,0:04:16.85,Default,,0000,0000,0000,,Fertilization can occur \Nby one of two techniques.
Dialogue: 0,0:04:16.85,0:04:20.31,Default,,0000,0000,0000,,In the first, the eggs are incubated\Nwith thousands of sperm
Dialogue: 0,0:04:20.31,0:04:24.72,Default,,0000,0000,0000,,and fertilization occurs naturally\Nover a few hours.
Dialogue: 0,0:04:24.72,0:04:27.84,Default,,0000,0000,0000,,The second technique maximizes\Ncertainty of fertilization
Dialogue: 0,0:04:27.84,0:04:32.46,Default,,0000,0000,0000,,by using a needle \Nto place a single sperm inside the egg.
Dialogue: 0,0:04:32.46,0:04:37.18,Default,,0000,0000,0000,,This is particularly useful when there is\Na problem with the quality of the sperm.
Dialogue: 0,0:04:37.18,0:04:41.82,Default,,0000,0000,0000,,After fertilization, embryos can be \Nfurther screened for genetic suitability,
Dialogue: 0,0:04:41.82,0:04:44.48,Default,,0000,0000,0000,,frozen for later attempted pregnancies,
Dialogue: 0,0:04:44.48,0:04:48.69,Default,,0000,0000,0000,,or delivered into the woman's uterus\Nvia catheter.
Dialogue: 0,0:04:48.69,0:04:53.91,Default,,0000,0000,0000,,Common convention is to transfer\Nthe embryo three days after fertilization,
Dialogue: 0,0:04:53.91,0:04:56.54,Default,,0000,0000,0000,,when the embryo has eight cells,
Dialogue: 0,0:04:56.54,0:05:01.14,Default,,0000,0000,0000,,or on day five, when\Nthe embryo is called a blastocyst,
Dialogue: 0,0:05:01.14,0:05:03.77,Default,,0000,0000,0000,,and has hundreds of cells.
Dialogue: 0,0:05:03.77,0:05:08.72,Default,,0000,0000,0000,,If the woman's eggs are of poor quality\Ndue to age or toxic exposures,
Dialogue: 0,0:05:08.72,0:05:11.48,Default,,0000,0000,0000,,or have been removed due to cancer,
Dialogue: 0,0:05:11.48,0:05:14.24,Default,,0000,0000,0000,,donor eggs may be used.
Dialogue: 0,0:05:14.24,0:05:18.67,Default,,0000,0000,0000,,In the case that the intended mother\Nhas a problematic uterus, or lacks one,
Dialogue: 0,0:05:18.67,0:05:22.62,Default,,0000,0000,0000,,another woman, called \Nthe gestational carrier or surrogate,
Dialogue: 0,0:05:22.62,0:05:26.45,Default,,0000,0000,0000,,can use her uterus to carry the pregnancy.
Dialogue: 0,0:05:26.45,0:05:28.38,Default,,0000,0000,0000,,To increase the odds of success,
Dialogue: 0,0:05:28.38,0:05:32.33,Default,,0000,0000,0000,,which are as high as 40%\Nfor a woman younger than 35,
Dialogue: 0,0:05:32.33,0:05:36.54,Default,,0000,0000,0000,,doctors sometimes transfer\Nmultiple embryos at once,
Dialogue: 0,0:05:36.54,0:05:39.51,Default,,0000,0000,0000,,which is why IVF results \Nin twins and triplets
Dialogue: 0,0:05:39.51,0:05:43.05,Default,,0000,0000,0000,,more often than natural pregnancies.
Dialogue: 0,0:05:43.05,0:05:48.00,Default,,0000,0000,0000,,However, most clinics seek to minimize\Nthe chances of multiple pregnancies,
Dialogue: 0,0:05:48.00,0:05:51.73,Default,,0000,0000,0000,,as they are riskier \Nfor mothers and babies.
Dialogue: 0,0:05:51.73,0:05:56.34,Default,,0000,0000,0000,,Millions of babies, like Louise Brown,\Nhave been born from IVF
Dialogue: 0,0:05:56.34,0:05:59.50,Default,,0000,0000,0000,,and have had normal, healthy lives.
Dialogue: 0,0:05:59.50,0:06:02.73,Default,,0000,0000,0000,,The long-term health consequences\Nof ovarian stimulation
Dialogue: 0,0:06:02.73,0:06:05.88,Default,,0000,0000,0000,,with IVF medicines are less clear,
Dialogue: 0,0:06:05.88,0:06:09.92,Default,,0000,0000,0000,,though so far, IVF seems safe for women.
Dialogue: 0,0:06:09.92,0:06:11.88,Default,,0000,0000,0000,,Because of better genetic testing,
Dialogue: 0,0:06:11.88,0:06:13.71,Default,,0000,0000,0000,,delayed childbearing, \N
Dialogue: 0,0:06:13.71,0:06:16.76,Default,,0000,0000,0000,,increased accessibility\Nand diminishing cost,
Dialogue: 0,0:06:16.76,0:06:22.58,Default,,0000,0000,0000,,it's not inconceivable that artificial\Nbaby making via IVF and related techniques
Dialogue: 0,0:06:22.58,0:06:26.72,Default,,0000,0000,0000,,could outpace natural reproduction\Nin years to come.