The proportion of pregnancies that end in miscarriage is MUCH higher than that. Many "pregnancies" (read: fertilized ova) don't implant in the uterus or implant and fail to progress which ends up looking like a heavy period that's a little late. Judging the start of "life" as fertilization is absolutely inane because of how many fertilized ova just don't make it past 16 cells or so.
I was referring to the many instances in which the blastocyst does implant, but fails to grow past the initial stages of development. Progression to the point of differentiation of tissues is the hurdle that many fertilized ova fail to clear. Failure of implantation is still important to discuss in the political context given that there are so many people with an absolute absence of biology education that think that life begins at fertilization.
The issue comes from the fact that if there's any amount of implantation and the very earliest stages of development, a pregnancy test will come back positive and there are many diagnostic tests (most imaging modalities) and many procedures (such as non-obstetrical emergency surgeries) that will get delayed or sometimes even denied because of the positive pregnancy test. Every AFAB that comes through an ER that might need imaging gets a point-of-care pregnancy test that has to come back negative for something like a CT scan unless it is a very dire situation because of the radiation risk to a developing embryo.
Obstetrical procedures like abortions are not the only ones that are gate-kept for AFAB patients because of the policies surrounding risks to developing embryos or fetuses.
Edit to add: The studies do say that the estimated incidence of clinically unrecognized pregnancies is approximately 20%, but given the myriad risk factors that can feed into that outcome, things like exposures, stresses, SES, and access to medical care may increase that incidence rate in some populations.
Abortion is the treatment for miscarriage, hospitals in some US states (read: third-world hell-holes) are refusing to treat mothers miscarrying as their fascist overlords state government officials have fully banned all abortions. The hospital staff could literally go to jail for saving the life of a dying woman who's pregnancy failed naturally. So you end up with situations like this where mothers just die in the parking lot of the hospital. I imagine they get to come in after that though, no more potential abortions and the morgue is probably right there in the basement! How convenient.