"Spontaneous abortion is the loss of pregnancy naturally before twenty weeks of gestation. Colloquially, spontaneous abortion is referred to as a 'miscarriage' to avoid association with induced abortion."

Important part of table 4: "†Data on pregnancy loss are based on 827 participants in the v-safe pregnancy registry who received an mRNA Covid-19 vaccine (BNT162b2 [Pfizer–BioNTech] or mRNA-1273 [Moderna]) from December 14, 2020, to February 28, 2021, and who reported a completed pregnancy. A total of 700 participants (84.6%) received their first eligible dose in the third trimester."

And so when you link the definition of spontaneous abortion with the data, that means the 700 pregnant women who received their first eligible dose in the third trimester, it is impossible for them to have a spontaneous abortion, because this only occurs within the first 20 weeks of pregnancy.

So then we have 127 eligible women left who have the possibility to have a spontaneous abortion, and 104 of those 127 women had spontaneous abortions. Unless they labeled terms incorrectly, that does look like 104 out of 127 eligible pregnant women in their first trimester experienced spontaneous abortion or "miscarriage". The other 700 women can't even have a spontaneous abortion, and the author of the article rightfully says they might as well have been 700 men.