New Study Says That A Significantly Higher Risk Of Pregnancy Complications In Neanderthals May Have Contributed To The Extinction Of Their Species

For many years, our ancient ancestors lived alongside Neanderthals. Sometimes the various tribes would compete and fight, other times they would work together, and even procreate. At some point, however, the Neanderthals died out and went extinct, and our ancestors went on to thrive and become the dominant species on the planet.

There were undoubtedly many factors that contributed to the extinction of Neanderthals, but a new study published in the Journal of Reproductive Immunology suggests that complications due to pregnancy could have had a major impact.

The complication that likely caused major issues is something that humans today still experience. Preeclampsia and eclampsia. These are issues where there is a lack of blood flow to the developing fetus, which will often cause fetal growth restriction (FGR). In addition to being very dangerous for the fetus, it can also cause dangerously high blood pressure and even seizures in the mother.

It is estimated that between 2 and 8% of human pregnancies experience some level of preeclampsia, and about 1% have eclampsia. Fortunately, modern medicine is able to treat the issue quite successfully, but it is still responsible for around 70,000 maternal deaths each year around the world as well as about 500,000 fetal deaths.

While dangerous, about 75% of cases where the fetus has FGR happen without the mother experiencing preeclampsia. The researchers believe that this means that our species has developed some type of safeguard to minimize the risk. Neanderthals, they propose, likely did not have this safeguard.

If that is the case, they estimate that the rates of preeclampsia would be between 10-20%, and the rate of eclampsia would be 4-5%. This would cause around 4% of all first-time pregnancies to result in the death of the mother, which would be devastating on the species. The researchers wrote:

“From an evolutionary medicine perspective, the emergence of a reproductive safeguard in which most pregnancies with superficial placentation do not precipitate a life-threatening maternal syndrome would have been essential for human survival.”

So, if Homo sapiens developed a protection from this issue and Neanderthals did not, it would give us a serious advantage that may have contributed to our success and their extinction.

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