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Exactly, and the reason why infant mortality has gone down also has a twist to it that's usually spun for profit. It's not due to heroic advances in obstetrics, nutrition, or even medical care in general, but rather fertility demographic changes.

If you're in a metro area, go to your nearest hospital with a labor wing and ask any nurse on staff if they can describe any pattern between characteristics of a woman and how fast she delivers her offspring. The greatest predictor of risk in death of either an infant or a mother in childbirth is duration of labor. The second greatest predictor of labor death risk is age of the mother.

A growing trend in fertility for a long time by now is positive correlation with poverty, illiteracy, and religious susceptibility. There's also a very effective self-interested cultural and economical push towards _certain_ women fully embracing the (in)action of stopping their lineage either actively through choice or even passively through delay by necessity against the ticking time bomb that is menopause to receive better individual outcomes than creating children for sake of retirement insurance when now such old-age risk can now be offloaded to a pooled global society that has a huge reserve of more fertility-friendly cultures. In addition legal incentives and even unintended economic punishments push _certain_ demographics of males towards rationally opting out of procreation in order to stave off undesirable consequences for their wealth and happiness.

Tangentially, it's not something that people like to talk about in public discourse, but there has also been a very prominent trend of decreasing age in the arrival of puberty especially for girls.

All of these factors are are the outcomes of individuals, demographics, and society in general implementing changes to their reproductive strategies and over time these choices reinforce themselves through natural selection. And of course this will reflect on some opaque metrics such as "average life expectancy" if you are not able to sub-categorize the averages.