Consider this: not so long ago, it was thought that newborns could not feel pain. Surgery was carried out on newborn and premature infants with minimal or no anesthesia.
Twenty-five years ago, when Kanwaljeet Anand was a medical resident in a neonatal intensive care unit, his tiny patients, many of them preterm infants, were often wheeled out of the ward and into an operating room. He soon learned what to expect on their return. The babies came back in terrible shape: their skin was gray, their breathing shallow, their pulses weak. Anand spent hours stabilizing their vital signs, increasing their oxygen supply and administering insulin to balance their blood sugar. “What’s going on in there to make these babies so stressed?” Anand wondered. “That’s when I discovered that the babies were not getting anesthesia,” he recalled recently. Infants undergoing major surgery were receiving only a paralytic to keep them still. Anand’s encounter with this practice occurred at John Radcliffe Hospital in Oxford, England, but it was common almost everywhere. Doctors were convinced that newborns’ nervous systems were too immature to sense pain, and that the dangers of anesthesia exceeded any potential benefits.
Since 1986, this practice has been unacceptable, and it is recognized that they can experience severe pain. Today, adequate pain relief for even the youngest infants is the standard of care.
As NICU technology improved, the preterm infants he cared for grew younger and younger — with gestational ages of 24 weeks, 23, 22 — and he noticed that even the most premature babies grimaced when pricked by a needle. “So I said to myself, could it be that this pain system is developed and functional before the baby is born?” It was not an abstract question: fetuses as well as newborns may now go under the knife. Once highly experimental, fetal surgery is a frequent occurrence at a half-dozen fetal treatment centers around the country, and could soon become standard care for some conditions diagnosed prenatally like spina bifida. Whether the fetus feels pain is a question that matters to the doctor wielding the scalpel. If the notion that newborns are incapable of feeling pain was once widespread among doctors, a comparable assumption about fetuses was even more entrenched.
In 1994, an article in a British medical journal, the Lancet, revealed hormonal stress reactions in the fetus. The article concluded with the recommendation that painkillers be used when surgery is done on the fetus. The authors wrote, “This applies not just to diagnostic and therapeutic procedures on the fetus, but possibly also to termination of pregnancy, especially by surgical techniques involving dismemberment.” In 1991, scientific advisors to the Federal Medical Council in Germany had made a similar recommendation. And the Australian national Health and Medical Research Council requires painkillers to be used on the fetuses of animals. In 1997, the Royal College of Obstetricians and Gynecologists reported that the fetus could not feel pain until 26 weeks, but urged anesthesia from 24 weeks. In August 2001, however, Great Britain’s Medical Research Council revised that conclusion and said that pain perception may be as early as 20 weeks. Another Parliamentary group of 15 scientists from Britain, Ireland and Australia concluded that the mechanisms for pain perception are in place and functional before the 10th week of gestation.
Nicholas Fisk is a fetal-medicine specialist and director of the University of Queensland Center for Clinical Research in Australia. For years, he says, “I would be doing a procedure to a fetus, and the mother would ask me, ‘Does my baby feel pain?’ The traditional, knee-jerk reaction was, ‘No, of course not.’ ” But research in Fisk’s laboratory (then at Imperial College in London) was making him uneasy about that answer. It showed that fetuses as young as 18 weeks react to an invasive procedure with a spike in stress hormones and a shunting of blood flow toward the brain — a strategy, also seen in infants and adults, to protect a vital organ from threat. Fisk selected 45 fetuses that required a potentially painful blood transfusion, giving one-third of them an injection of the potent painkiller fentanyl. As with Anand’s experiments, the results were striking: in fetuses that received the analgesic, the production of stress hormones was halved, and the pattern of blood flow remained normal. Fisk says he believes that his findings provide suggestive evidence of fetal pain.
Pain cannot be measured directly. What has to be examined, in the case of babies, are things like stress reactions measured by the release of certain hormones in the blood, and the presence of the various anatomical structures necessary for the transmission and perception of pain. In the absence of first-person testimony, Fisk concludes, it’s “better to err on the safe side.”
A lot of the uncertainty revolves around the fact that we still do not know all the physiological elements necessary for pain perception. What is becoming clearer, however, is that pain perception is not something limited to one or another area of the brain; nor is it something that suddenly “turns on” at one specific point in development. Anand acknowledges that the cerebral cortex is not fully developed in the fetus until late in gestation. What is up and running, he points out, is a structure called the subplate zone, which some scientists believe may be capable of processing pain signals, a kind of holding station for developing nerve cells, which eventually melds into the mature brain. The fetus’s undeveloped state, in other words, may not preclude it from feeling pain.
In fact, the unborn may actually feel more pain than the adult , not less: the body’s mechanisms for inhibiting pain and making it more bearable do not become active until after birth. Although the tools needed to feel pain do function, the mechanism needed to reduce the pain naturally does not. In newborns, nerve pathways that carry pain-inhibiting messages from the brain stem to the spinal cord mature later than other parts of the system.
The fetus is not a “little adult,” Anand says, and we shouldn’t expect it to look or act like one. Rather, it’s a singular being with a life of the senses that is different, but no less real, than our own.
The capacity to feel pain has often been put forth as proof of a common humanity. Likewise, a presumed insensitivity to pain has been used to exclude some from humanity’s privileges and protections. Many 19th-century doctors believed blacks were indifferent to pain and performed surgery on them without even that era’s rudimentary anesthesia. Over time, the circle of those considered “alive to pain,” and therefore fully human, has widened to include members of other religions and races, the poor, the criminal, the mentally ill — and, thanks to the work of Anand and others, the very young. Should the circle enlarge once more, to admit those not yet born? Should fetuses be added to what Martin Pernick, a historian of the use of anesthesia, has called “the great chain of feeling”? Anand maintains that they should.
