The artificial womb exists. In Tokyo, researchers have developed a technique called EUFI — extrauterine fetal
incubation. They have taken goat fetuses, threaded catheters through
the large vessels in the umbilical cord and supplied the fetuses with
oxygenated blood while suspending them in incubators that contain
artificial amniotic fluid heated to body temperature.
For a moment, as you contemplate those
fetal goats, it may seem a short hop to the Central Hatchery of Aldous
Huxley’s imagination. In fact, in recent decades, as medicine has
focused on the beginning and end stages of pregnancy, the essential time
inside the woman’s body has been reduced. We are, however, still a long
way from connecting those two points, from creating a completely
artificial gestation. But we are at a moment when the fetus, during its
obligatory time in the womb, is no longer inaccessible, no longer locked
away from medical interventions.
The future of human reproductive medicine
lies along the speeding trajectories of several different technologies.
There is neonatology, accomplishing its miracles at the too-abrupt end
of gestation. There is fetal surgery, intervening dramatically during
pregnancy to avert the anomalies that kill and cripple newborns. There
is the technology of assisted reproduction, the in-vitro fertilization
and gamete retrieval-and-transfer fireworks of the last 20 years. And
then, inevitably, there is genetics. All these technologies are
essentially new, and with them come ethical questions so potent that the
very inventors of these miracles seem half-afraid of where we may be
heading.
Between Womb and Air
Between Womb and Air
Modern neonatology is a relatively short
story: a few decades of phenomenal advances and doctors who resuscitate
infants born 16 or 17 weeks early, babies weighing less than a pound.
These very low-birthweight babies have a survival rate of about 10
percent. Experienced neonatologists are extremely hesitant about pushing
the boundaries back any further; much research is aimed now at reducing
the severe morbidity of these extreme preemies who do survive.
”Liquid preserves the lung structure and
function,” says Thomas Shaffer, professor of physiology and pediatrics
at the School of Medicine at Temple University. He has been working on
liquid ventilation for almost 30 years. Back in the late 1960’s, he
looked for a way to use liquid ventilation to prevent decompression
sickness in deep-sea divers. His technology was featured in the book
”The Abyss,” and for the movie of that name, Hollywood built models of
the devices Shaffer had envisioned. As a postdoctoral student in
physiology, he began working with premature infants. Throughout
gestation, the lungs are filled with the appropriately named fetal lung
fluid. Perhaps, he thought, ventilating these babies with a liquid that
held a lot of oxygen would offer a gentler, safer way to take these
immature lungs over the threshold toward the necessary goal of breathing
air. Barotrauma, which is damage done to the lungs by the forced air
banging out of the ventilator, would thus be reduced or eliminated.
Today, in Shaffer’s somewhat labyrinthine
laboratories in Philadelphia, you can come across a ventilator with
pressure settings that seem astoundingly low; this machine is set at
pressures that could never force air into stiff newborn lungs. And then
there is the long bubbling cylinder where a special fluorocarbon liquid
can be passed through oxygen, picking up and absorbing quantities of
oxygen molecules. This machine fills the lungs with fluid that flows
into the tiny passageways and air sacs of a premature human lung.
Shaffer remembers, not long ago, when
many people thought the whole idea was crazy, when his was the only team
working on filling human lungs with liquid. Now, liquid ventilation is
cited by many neonatologists as the next large step in treating
premature infants. In 1989, the first human studies were done, offering
liquid ventilation to infants who were not thought to have any chance of
survival through conventional therapy. The results were promising, and
bigger trials are now under way. A pharmaceutical company has developed a
fluorocarbon liquid that has the capacity to carry a great deal of
dissolved oxygen and carbon dioxide — every 100 milliliters holds 50
milliliters of oxygen. By putting liquid into the lung, Shaffer and his
colleagues argue, the lung sacs can be expanded at a much lower
pressure.
”I wouldn’t want to push back the
gestational age limit,” Shaffer says. ”I want to eliminate the damage.”
He says he believes that this technology may become the standard. By the
year 2000, these techniques may be available in large centers. Pressed
to speculate about the more distant future, he imagines a premature baby
in a liquid-dwelling and a liquid-breathing intermediate stage between
womb and air: Immersed in fluid that would eliminate insensible water
loss you would need a sophisticated temperature-control unit, a
ventilator to take care of the respiratory exchange part, better thermal
control and skin care.
The Fetus as Patient
The notion that you could perform surgery
on a fetus was pioneered by Michael Harrison at the University of
California in San Francisco. Guided by an improved ultrasound
technology, it was he who reported, in 1981, that surgical intervention
to relieve a urinary tract obstruction in a fetus was possible.
”I was frustrated taking care of
newborns,” says N. Scott Adzick, who trained with Harrison and is
surgeon in chief at the Children’s Hospital of Philadelphia.
When children are born with
malformations, damage is often done to the organ systems before birth;
obstructive valves in the urinary system cause fluid to back up and
destroy the kidneys, or an opening in the diaphragm allows loops of
intestine to move up into the chest and crowd out the lungs. ”It’s like a
lot of things in medicine,” Adzick says, ”if you’d only gotten there
earlier on, you could have prevented the damage. I felt it might make
sense to treat certain life-threatening malformations before birth.”
Adzick and his team see themselves as
having two patients, the mother and the fetus. They are fully aware that
once the fetus has attained the status of a patient, all kinds of
complex dilemmas result. Their job, says Lori Howell, coordinator of
Children’s Hospital’s Center for Fetal Diagnosis and Treatment, is to
help families make choices in difficult situations. Terminate a
pregnancy, sometimes very late? Continue a pregnancy, knowing the fetus
will almost certainly die? Continue a pregnancy, expecting a baby who
will be born needing very major surgery? Or risk fixing the problem in
utero and allow time for normal growth and development?
The first fetal surgery at Children’s
Hospital took place seven months ago. Felicia Rodriguez, from West Palm
Beach, Fla., was 22 weeks pregnant. Through ultrasound, her fetus had
been diagnosed as having a congenital cystic adenomatoid malformation a
mass growing in the chest, which would compress the fetal heart, backing
up the circulation, killing the fetus and possibly putting the mother
into congestive heart failure.
When the fetal circulation started to
back up, Rodriguez flew to Philadelphia. The surgeons made a
Caesarean-type incision. They performed a hysterotomy by opening the
uterus quickly and bloodlessly, and then opened the amniotic sac and
brought out the fetus’s arm, exposing the relevant part of the chest.
The mass was removed, the fetal chest was closed, the amniotic membranes
sealed with absorbable staples and glue, the uterus was closed and the
abdomen was sutured. And the pregnancy continued — with special
monitoring and continued use of drugs to prevent premature labor. The
uterus, no longer anesthetized, is prone to contractions. Rodriguez gave
birth at 35 weeks’ gestation, 13 weeks after surgery, only 5 weeks
before her due date. During those 13 weeks, the fetal heart pumped
normally with no fluid backup, and the fetal lung tissue developed
properly. Roberto Rodriguez 3d was born this May, a healthy baby born to
a healthy mother.
This is a new and remarkable technology.
Children’s Hospital of Philadelphia and the University of California at
San Francisco are the only centers that do these operations, and fewer
than a hundred have been done. The research fellows, residents working
in these labs and training as the next generation of fetal surgeons,
convey their enthusiasm for their field and their mentors in everything
they say. When you sit with them, it is impossible not to be dazzled by
the idea of what they can already do and by what they will be able to
do. ”When I dare to dream,” says Theresa Quinn, a fellow at Children’s
Hospital, ”I think of intervening before the immune system has time to
mature, allowing for advances that could be used in organ
transplantation to replacement of genetic deficiencies.”
But What Do We Want?
But What Do We Want?
Eighteen years ago, in-vitro
fertilization was tabloid news: test-tube babies! Now IVF is a standard
therapy, an insurance wrangle, another medical term instantly understood
by most lay people. Enormous advertisements in daily newspapers offer
IVF, egg-donation programs, even the newer technique of ICSI
intracytoplasmic sperm injection as consumer alternatives. It used to
be, for women at least, that genetic and gestational motherhood were one
and the same. It is now possible to have your own fertilized egg
carried by a surrogate or, much more commonly, to go through a pregnancy
carrying an embryo formed from someone else’s egg.
Given the strong desire to be pregnant,
which drives many women to request donor eggs and go through biological
motherhood without a genetic connection to the fetus, is it really very
likely that any significant proportion of women would take advantage of
an artificial womb? Could we ever reach a point where the desire to
carry your own fetus in your own womb will seem a willful rejection of
modern health and hygiene, an affected earth-motherism that flies in the
face of common sense — the way I feel about mothers in Cambridge who
ostentatiously breast-feed their children until they are 4 years old?
I would argue that God in her wisdom
created pregnancy so Moms and babies could develop a relationship before
birth, says Alan Fleischman, professor of pediatrics at Albert Einstein
College of Medicine in New York, who directed the neonatal program at
Montefiore Medical Center for 20 years.
Mary Mahowald, a professor at the MacLean
Center for Clinical Medical Ethics at the University of Chicago, and
one of her medical students surveyed women about whether they would
rather be related to a child gestationally or genetically, if they
couldn’t choose both. A slight majority opted for the gestational
relationship, caring more about carrying the pregnancy, giving birth and
nursing than about the genetic tie. ”Pregnancy is important to women,”
Mahowald says. ”Some women might prefer to be done with all this — we
hire our surrogates, we hire our maids, we hire our nannies — but I
think these things are going to have very limited interest.”
Susan Cooper, a psychologist who counsels people going through
infertility workups, isn’t so sure. Yes, she agrees, many of the
patients she sees have ”an intense desire to be pregnant but it’s hard
to know whether that’s a biological urge or a cultural urge.”
And Arthur L. Caplan, director of the Center for Bioethics at the University of Pennsylvania, takes it a step further. Thirty years from now, he speculates, we will have solved the problem of lung development; neonatology will be capable of saving 15- and 16-week-old fetuses. There will be many genetic tests available, easy to do, predicting the risks of acquiring late-onset diseases, but also predicting aptitudes, behavior traits and aspects of personality. There won’t be an artificial womb available, but there will be lots of prototypes, and women who can’t carry a pregnancy will sign up to use the prototypes in experimental protocols. Caplan also predicts that ”there will be a movement afoot which says all this is unnecessary and unnatural, and that the way to have babies is sex and the random lottery of nature a movement with the appeal of the environmental movement today.” Sixty years down the line, he adds, the total artificial womb will be here. ”It’s technologically inevitable. Demand is hard to predict, but I’ll say significant.”
It all used to happen in the dark — if it happened at all. It occurred well beyond our seeing or our intervening, in the wet, lightless spaces of the female body. So what changes when something as fundamental as human reproduction comes out of the closet, so to speak? Are we, in fact, different if we take hands-on control over this most basic aspect of our biology? Should we change our genetic trajectory and thus our evolutionary path? Eliminate defects or eliminate differences or are they one and the same? Save every fetus, make every baby a wanted baby, help every wanted child to be born healthy — are these the same? What are our goals as a society, what are our goals as a medical profession, what are our goals as individual parents — and where do these goals diverge?
”The future is rosy for bioethicists,” Caplan says.
Perri Klass’s most recent book is ”Baby Doctor.” She is a pediatrician at Boston Medical Center.
And Arthur L. Caplan, director of the Center for Bioethics at the University of Pennsylvania, takes it a step further. Thirty years from now, he speculates, we will have solved the problem of lung development; neonatology will be capable of saving 15- and 16-week-old fetuses. There will be many genetic tests available, easy to do, predicting the risks of acquiring late-onset diseases, but also predicting aptitudes, behavior traits and aspects of personality. There won’t be an artificial womb available, but there will be lots of prototypes, and women who can’t carry a pregnancy will sign up to use the prototypes in experimental protocols. Caplan also predicts that ”there will be a movement afoot which says all this is unnecessary and unnatural, and that the way to have babies is sex and the random lottery of nature a movement with the appeal of the environmental movement today.” Sixty years down the line, he adds, the total artificial womb will be here. ”It’s technologically inevitable. Demand is hard to predict, but I’ll say significant.”
It all used to happen in the dark — if it happened at all. It occurred well beyond our seeing or our intervening, in the wet, lightless spaces of the female body. So what changes when something as fundamental as human reproduction comes out of the closet, so to speak? Are we, in fact, different if we take hands-on control over this most basic aspect of our biology? Should we change our genetic trajectory and thus our evolutionary path? Eliminate defects or eliminate differences or are they one and the same? Save every fetus, make every baby a wanted baby, help every wanted child to be born healthy — are these the same? What are our goals as a society, what are our goals as a medical profession, what are our goals as individual parents — and where do these goals diverge?
”The future is rosy for bioethicists,” Caplan says.
Perri Klass’s most recent book is ”Baby Doctor.” She is a pediatrician at Boston Medical Center.
No comments:
Post a Comment