"Misreporting" is a strong term. While I'm sure a few countries (e.g. the Communist Paradise of Cuba) do misreport their statistics, many other countries get different answers via reasonable disagreement on definitions.
Consider an 5 month old fetus who completely passed through the vagina, takes one breath and dies. Is that infant mortality or miscarriage? Now make it 6 months old, but he didn't take any breaths. Or 7 months, the head (but not body) passed through the vagina, then he dies. Or 7 months, body but not head passed through vagina. If you want to draw distinctions between miscarriage and infant mortality you need to draw a more or less arbitrary line. Not every nation draws the line in the same place and the statistics are therefore incomparable.
You are right about the effect this has on the statistics. I'm just suggesting that there are far less nefarious reasons than misreporting stats.
Calling it misreporting is harsh, but the implication of not counting some babies is that they weren't really people. I think that's worth thinking about.
Also, calling a fully-born human being a fetus is both inaccurate and even more harsh than this use of the word "misreporting".
For the sake of furthering on-topic discussion, let's all agree that infant mortality is a different problem than longevity and therefore a better measure than "life expectancy from birth" would be "life expectancy from age 1" or something along those lines.
Consider an 5 month old fetus who completely passed through the vagina, takes one breath and dies. Is that infant mortality or miscarriage? Now make it 6 months old, but he didn't take any breaths. Or 7 months, the head (but not body) passed through the vagina, then he dies. Or 7 months, body but not head passed through vagina. If you want to draw distinctions between miscarriage and infant mortality you need to draw a more or less arbitrary line. Not every nation draws the line in the same place and the statistics are therefore incomparable.
You are right about the effect this has on the statistics. I'm just suggesting that there are far less nefarious reasons than misreporting stats.