Historically women had a relatively high chance of dying while giving birth.

At first thought it seems to me that this would be a disadvantage for the species for the obvious reason that a dead person can no longer give birth (and can't care for her offspring).

Is this outweighed by some advantages? I can imagine that there would be some evolutionary advantage to have the "weaker" women die during child birth and let the "stronger" ones live to produce more children with "stronger" genes.

Or is the high mortality rate in humans during child birth a result of civilization (pre-moderne civilization of course, with the general lack of hygiene/medical knowledge)?

What is it like for the relatively un-civilized tribes around the world?

How is it compared to other closely related mammals?

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    $\begingroup$ Dying during or shortly after birth has two main reasons: First is bleeding to death when the big blood vessels which support the developing embryo are not closed correctly or if the placenta gets stuck. The other are infections to wounds that occur during birth as tetanus infections. While the second is mostly a problem in less developed countries, the first still happens and can be very dangerous. The death rate went down pretty much, when doctors and midwifes started taking basic hygienic measures. $\endgroup$
    – Chris
    Apr 9, 2014 at 15:24

2 Answers 2


That's an interesting question. And it is also a common misunderstanding of evolutionary processes.

Thanks to @Chris comment, we know/can assume that high mortality rate is not a consequence of industrialization but has ever been before the era of modern medicine.

Women don't let themselves die in order to improve the species. Those women that carry a gene forcing them to commit suicide in order to improve the species won't pass on their genes, and in consequence no women will ever suicide in order to improve the species. In other words, altruistic behavior cannot appear and spread over time. This is the standard view of selection (and probably the good explanation in our case).

Now, I have to say that I lied in the previous paragraph! There is a field of study called social evolution which aims to study social traits. Social traits are those traits which influence not only the fitness of the individual carrying the trait but also the fitness of other individuals in the population. Theoretically all traits are somehow social traits! Typically altruistic behavior is among those social traits that cause a decrease (a cost) in the carrier fitness for an advantage (a benefit) for one or several other individuals in the population. There are several models (which are still debated in particular concerning the assumptions of these models) to explain the evolution of such traits. The most famous, most commonly used and most theoretically studied one is Kin selection/Hamilton's rule. You'll find some explanations about this rule on this post. The concept of population structure is key in the understanding of Hamilton's rule. Also important are the concept of levels of selection, which gives a possible explanation for the evolution of altruism, the concept of lineage selection, and finally the concept of reciprocity (but that doesn't make much sense in the current context!). Some people would not classify these models as I did, some would add other models, some would melt two models into one…

For one of these models to be correct we would need high lineage split and extinctions in human history which I don't think is really the case. Or we'd need that the death of a woman is particularly benefit to her family. I don't think first human were cannibals. Women were probably very often pregnant and males had to fight to be the father. So dying would probably not free much opportunities for the sisters and brothers…. One would need to write some equations and gather more information than what I have but intuitively I don't think that high mortality rate in women while giving birth is an altruistic behavior.


Human females have one of the worst chidbirth experiences. This is because of our extremely high cranial capacity compared to the apes. This had an obvious evolutionary advantage and made us what we are today. However this creates problems as the braincase has to pass the pelvic cavity during childbirth. The wider hips in women compensate for this but still it is much harder than in case of other apes. Shorter women are in greater danger. Much easier for our closest cousins the chimps or gorillas. Compared to tribal women the civilised lineages have survived with more assistance...


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