In pregnancy, the mammalian womb maintains a carefully controlled environment that allows the exchange of all the substances between the mother's blood and the blood of the foetus. The vessels from the mother and the foetus come together in the elaborate tangle we know as the placenta. The two blood supplies don't mix, but the vessels come close together and capillaries from the foetus and mother are very thin, just one cell thick, and even have small holes (known as fenestrations) that allow fluid and small molecules to leave or enter by diffusion. The foetus obtains all the biological molecules it needs through this exchange with stuff from the mother's blood, including oxygen and glucose for respiration, amino acids to build proteins, some hormones, antibodies, electrolytes like sodium, potassium, chloride and calcium ions, as well as a range of other useful substances.
Considering the complexity of pregnancy and the growth of a foetus, it comes as no surprise that there are an incredible number of things that can go wrong and one of the outcomes of this may be premature birth. Researchers from Tohoku University in Japan have recently published their work using an artificial womb that successfully kept lamb foetuses alive for a week (the length of time that the experiment was designed for).
The system they use is called ex-vivo uterine environment (EVE) therapy, which is essentially a plastic bag with a very carefully controlled liquid environment to supply all the substances, temperature, pH etc needed to support foetal growth.
In this particular experiment, ewes were delivered about three-quarters of the way through their gestation - this is around the equivalent of a two-month early human baby. Their growth and healthy development over the following seven days in the artificial womb was monitored in various ways, including: measuring the growth of their limb bones; the rate of their blood flow; and the growth of bacteria and the amount of inflammatory immune response. The measurements were compared to the development of control ewes who continued in a normal gestation. The researchers found there was no significant differences between development of the ewes in the artificial compare with the natural wombs.
Studies like this inevitably involve the death of the animals being studied. To do such research requires permission from regulatory bodies (organisations that enforce laws or regulations created by governments) which determine whether the experiment justifies the death of animals. Researchers have to carefully explain how they are using the smallest number of animals that they need to and that there is the minimum amount of distress and pain involved and that the outcomes provide useful information. This particular experiment shows how the artificial womb is a potentially effective way to treat premature babies and allows scientists to improve this system and bring it closer to the day when it could be used with very premature human babies.
Select sources:
https://www.sciencedaily.com/releases/2017/08/170817141714.htm
http://www.ajog.org/article/S0002-9378(17)30675-0/fulltext
