New moms and dads are always excited about a child taking her first steps. But baby steps are also happening in the world of biotechnology and eventually this will impact how babies are made.
You may have heard of the heart-lung machine. It enables what’s called cardiopulmonary bypass (CPB). Surgeons use CPB to keep people alive during certain operations when the heart must be disconnected from the blood vessels. In place of the patient’s heart, the equipment pumps blood through the body. In place of the patient’s lungs, the equipment adds oxygen to the blood and removes carbon dioxide. In a very real sense, CPB is analogous to a circulation bypass system that nature uses to support the fetus. Rather than going through the fetal lungs, fetal blood is directed into the mother, so her lungs can add oxygen and remove carbon dioxide.
CPB has been around since the 1950s, but the technology that allows it to substitute for a patient’s lungs has developed considerably. This has led to new devices that help patients breathe in a process called extracorporeal membrane oxygenation (ECMO). An ECMO device can act as a supplemental lung in critical situations, for instance when a patient’s lungs simply fail, to remove a patient gradually from CPB after a big heart operation, or to keep a patient going who is waiting for a heart transplant.
Along side these applications, ECMO technology also into a machine to help premature infants that researchers are calling an “artificial placenta”. You may know that the natural placenta connects the blood circulation of the mother to the blood circulation of the fetus. On its way from the fetus to the mother and back into the fetus, blood must pass through the placenta. The fetus is connected to the placenta by the umbilical cord, but when that stops at birth the newborn depends completely on its own lungs. This is a problem if a baby is born so prematurely that the lungs are not developed enough to support life. If the lungs can support the fetus, the fetus is said to be viable. Otherwise, it is called non-viable, but for decades technology has allowed doctors to compensate for a little bit of lung immaturity.
Using medicines given before birth, special sprays administered into the newborn lungs right after birth, and mechanical ventilators, obstetricians and neonatologists can make certain premature infants viable who would have died without modern medicine. The record for gestational age at birth of a surviving infant is 21 weeks and five days, set in 1987 and it was matched again in 2010. Earlier than about 23-24 weeks, survival is below 50 percent and drops quickly as gestational age and birth weight go down.
The ECMO device is really just a baby step toward an artificial placenta, since a real placenta does a lot more than give a fetus freshly oxygenated blood cells. But it’s a baby step that can change strategy. Rather than helping the lungs mature faster and using ventilators, the artificial placenta will allow doctors to let the lungs stay deflated. The circulation would stay in the pattern that existed inside the womb, but the baby would be outside. This would push the survival limit back from 21 weeks 5 days to a lower gestational age and that would be a big step to achieving what futurists have called ectogenesis –development in an artificial womb from conception to birth.