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
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?
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.
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