[Silent One]

80% of all miscarriages happen in the first trimester.

Is this on top of the roughly 66% spontaneously aborted of all conceptuses? (As per Soupart, a dear friend)

[semimojo]

Is this on top of the roughly 66% spontaneously aborted of all conceptuses?

I can't find any source getting close to that number = 20% seems to be the upper bound.

I expect the statistics I'm quoting are only counting cases where the pregnancy was known, and there's no way 2/3 of those abort.