From study limitations:
"We were unable to evaluate adverse outcomes that might occur in association with exposures earlier in pregnancy, such as congenital anoma- lies, because no pregnant persons who were vac- cinated early in pregnancy have had live births captured in the v-safe pregnancy registry to date; follow-up is ongoing. In addition, the proportion of pregnant persons who reported spontaneous abortion may not reflect true postvaccination proportions because participants might have been vaccinated after the period of greatest risk in the first trimester, and very early pregnancy losses might not be recognized. Whereas some pregnancies with vaccination in the first and early second trimester have been completed, the majority are ongoing, and a direct comparison of outcomes on the basis of timing of vaccina- tion is needed to define the proportion of spontaneous abortions in this cohort. Because of sample-size constraints, both pregnancy and neonatal outcomes were calculated as a proportion instead of a rate." What I bolded is part of the explanation for "what about the rest?" That's not quantitative though. They say the majority. Do they mean 51% are still awaiting an outcome?
However they acknowledge "very early pregnancy losses might not be recognized" which means they are implying the 104 or 105 is an undercount. Do they mean people didn't know if they were pregnant or not?