Like a Virgin Prasad, Aarathi (top 50 books to read .TXT) 📖

efficient, the way they function and what they can provide has essentially not changed in decades. While the incubators can provide warmth and humidity, they still cannot give any of the nutrients necessary for growth. Instead, a premature baby must have all those tubes inserted into his or her body to deliver ‘parenteral nutrition’, that is, the complete nutrition provided intravenously, via needle-like catheters inserted directly into the veins and bypassing the digestive system altogether. Yet more tubes passed through the nose and threaded to the stomach will give the child milk, if tests show its digestive system is able to take it. This care is incredibly challenging due to the extreme immaturity of the baby’s gut. In a mother’s womb, the stomach and gut will not digest food at such an early stage of gestation, but once out of the womb, a small amount of the mother’s breast milk will be used to acclimatize the baby’s stomach to its new environment. The baby will also be sedated, at least some of the time, to stop him or her from pulling the tubes out, and to decrease or prevent any discomfort or pain. Moreover, infection around the tubes is a serious threat, and can lead to severe problems for the child’s future health, should he or she survive. However you look at it, the incubators we have today are still a poor substitute for the relative security provided by the mother’s womb.

Over those same decades, doctors have been attempting to secure the viability of ever-more premature babies. To succeed, they will have to invent an incubator that is more womblike – something almost like the womb itself. One unlikely source of data into how a womblike incubator might work has come from studies of miscarriages that have occurred at the very earliest stages of pregnancy. By looking at pregnancies that have failed, researchers have been better able to understand how embryos implant into the womb. Some day, with this information, embryos might not only be created in the laboratory, through in vitro fertilization, but even be attached to an artificial placenta in an artificial womb and gestate there until they are ready to be born. Still, it’s one thing to cultivate sharks successfully in a man-made environment; it’s another to nurture humans in one.

Scientists in Japan and the United States are experimenting to find out if an artificial womb for humans might be feasible, using cells both in Petri dishes and in living animals to copy the inner workings of mammals. With all mammals, it is vital that newborns are able to discard the placenta when they leave the natural womb. The placenta, after all, is the life-support mechanism that allows a fertilized egg to develop into an embryo; it is also the frontline of development in protecting the foetus from infection and in providing nourishment. For this reason, when in the 1960s researchers first began to toil towards creating a machine that would stand in for the essential placenta, they faced many of the problems that intensive care doctors face when human babies are born prematurely. These problems proved especially challenging with their chosen subjects – goat foetuses.

During a further series of experiments in the 1980s, a team led by the late Professor Yoshinori Kuwabara encountered several serious setbacks. In particular, the goat foetuses moved, as all babies in the womb do – and some quite vigorously. During incubation, and especially once their condition was stable, the goat foetuses showed a variety of movements that would have been absolutely normal behaviour had they been in their mothers’ wombs. They rolled their eyes, moved their mouths, swallowed, breathed, twitched, wriggled, rolled, stretched, and moved their limbs. One even tried to stand up and run!

Although these movements were a positive sign, demonstrating that the foetuses in those primitive systems were active and seemingly stable, they caused malfunctions in the system; tubes got pulled out with all that wriggling. In fact, for the foetus that tried to stand up and run, the movements cost it its life. The animal sustained massive blood loss through the umbilical blood vessels, from which it had inadvertently pulled out its tubes. Other foetuses perished in the same way.

Swallowing also proved a problem. The foetuses did not drink out of thirst, but rather to help train the muscles of the throat and the digestive system during development – movements that are crucial for survival after birth. (Indeed, swallowing fluid inside the womb is the definition of redundant: a foetus’s body-water balance is maintained by the placenta.) In the environment of the artificial womb – a clear plastic tank about the size of a home aquarium filled with yellow liquid – the goat foetuses drank up their surroundings without any care for how much they ingested – and they ingested a lot. Several days after their incubation began, they had accumulated enough excessive fluids that their lungs became swollen. The fluid load also affected their developing cardiovascular system. The scientists were only able to continue the experiment by delivering sedatives and muscle relaxants to the goats, something that most human parents would be reluctant to see prescribed for their own child in an artificial womb, given the potential for life-long addiction.

In the 1980s, researchers in Tokyo were garnering the first promising results in experiments with goats and artificial placentas. Then in 2002, Kuwabara’s group developed an incubator consisting of a plastic tank filled with artificial amniotic fluid and a complete artificial placental system to provide oxygen into the blood directly, instead of via tubes into the veins. Unlike previous attempts, which only kept goat foetuses alive for about two days, the scientists reported that the foetuses placed in their fluid-filled plastic boxes stayed alive for three weeks. Like the wobbegongs, they too survived a trial birth. The artificial womb