About how many women have pregnant signs, then miscarry, but didn't realize they were pregnant?

Not many: Today many women do home tests in these circumstances thes tests are so accurate that not to know is rare.

Less than 1%: While it certainly possible to miscarry prior to confirmation of pregnancy, I do not receive many queries or meet many patients who have had that experience. Without a positve pregnancy test, there is no way to know with certainty that there ever was a pregnancy. I occasionally see a patient who had a positive home test who is negative at the office, who then knew they were pg b4 they miscarried.