When hundreds of millions of people are getting vaccinated you have to be very careful attributing anomalies to the vaccine and look at the overall numbers, i.e., did miscarriages go up overall after women started getting vaccinated. I am sure that before people started getting vaccinated there was a doctor that had 74% miscarriages in his practice. Statistically this would be a normal outlier and some other doctor would have zero miscarriages through his practice, both highly unlikely.

"Would a successful, highly regarded doctor blow up his career for a lie?"

Sure, for publicity people have been known to do all kinds of things. Again an outlier.