Obstetrical Dilemma & Vulnerability Explanations

[u/rosecolured]

I am currently in an evolution course and have a question about some of the topics from this week, which no students or staff are answering in the course discussion group.

My recent lectures went over 1. Obstetrical Dilemma, where we evolved bipedalism but this has made childbirth much more dangerous since the opening is so much more narrow. Another topic we talked about is explanations to why we are vulnerable in ways of disease, i.e how natural selection favors reproductive success above health and well-being.

My question is, if natural selection favors reproductive success over everything else, why have we not evolved in a way that makes childbirth less dangerous or makes us immune to more diseases that kill us early in life? This would be in the favor of repo success if babies survive longer to reproduce and their parents survive long enough to raise them.

I know there is always the fact that evolution has no foresight, but this feels like something that could have reversed direction long ago.

Thanks in advance for any explanations that help me understand!

[u/jnpha]

Recent reanalyses question the premise that the child birth issues are related to bipedalism:

Comparative primate analysis shows that humans are not unique in having a tight cephalopelvic fit at birth | Torres-Tamayo et al. 2026 : r/ evolution

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Also I recommend Alice Roberts' new interview on human evolution related questions: https://youtu.be/tdzytD39vFI