A recent study suggests that preeclampsia, a dangerous pregnancy complication, could have contributed to the extinction of Neanderthals. Researchers propose that this condition, linked to placental development, may have been more lethal to Neanderthals than to early Homo sapiens. However, leading paleoanthropologists view this idea as a highly speculative “thought experiment” with limited supporting evidence.
The Preeclampsia Hypothesis
The study, published in the Journal of Reproductive Immunology, argues that preeclampsia and its severe form, eclampsia, have been overlooked in discussions about Neanderthal reproductive health. These conditions, involving dangerously high blood pressure and potential organ damage, affect up to 8% of human pregnancies today and can be fatal to both mother and fetus.
The researchers hypothesize that Neanderthals may have lacked a crucial protective mechanism against preeclampsia, leading to increased maternal mortality and reduced reproductive success. This could have acted as an additional selective pressure, hastening their decline over centuries. The theory centers on the idea that the Neanderthal placenta, given shared genetic material with Homo sapiens, might have been prone to abnormal implantation, triggering preeclampsia.
Why This Matters: The Reproductive Bottleneck
The Neanderthals persisted for over 300,000 years before disappearing roughly 40,000 years ago. Their extinction remains one of paleontology’s biggest mysteries. Reproductive failure is a plausible factor in species decline, as low birth rates weaken populations over time. If Neanderthal pregnancies were systematically more dangerous, this could explain why they were eventually outcompeted by Homo sapiens, who may have had better pregnancy outcomes.
Expert Skepticism
However, experts in Neanderthal genetics and archaeology are not convinced. Patrick Eppenberger of the Institute of Evolutionary Medicine in Zurich argues that the claim that preeclampsia was a primary driver of extinction is not supported by current evidence. While he acknowledges the link between preeclampsia and human placental evolution, he points out that Neanderthals survived for hundreds of millennia.
Other researchers suggest that gene transfer between Homo sapiens and Neanderthals may have spread mitigating factors for preeclampsia, making the hypothesis less compelling. April Nowell, a Paleolithic archaeologist at the University of Victoria, notes that the search for a “smoking gun” cause of Neanderthal extinction is ongoing, but this study does not provide definitive proof.
Future Research
Despite skepticism, some experts agree that the theory is worth investigating. Analyzing genes related to maternal-fetal immunity and placental growth could potentially provide clues about Neanderthal reproductive health. However, obtaining conclusive evidence may be impossible without clinical data—which, of course, is unavailable for an extinct species.
Ultimately, the idea that preeclampsia doomed the Neanderthals remains a speculative hypothesis. It highlights the complex interplay of genetics, physiology, and environmental factors in the fate of our extinct relatives, but it lacks the firm evidence needed to declare it a primary cause of their disappearance.
