NEJM Covid-19 Vaccination - Pregnancy Case Study. Are there more studies??

Please see my outline and correct me if I am interpreting this information incorrectly....Just trying to better understand.

https://www.nejm.org/doi/full/10.1056/nejmoa2104983

Participants ages 18-54 years of age, at 12 weeks gestation or more. 

This is a very large age gap.  Clearly there were various factors involved, such as fertility assistance for those older participants. (More on this below) Shouldn't these participants be categorized by relevant clinical factors in order to properfly assess the risk vs benefit? 

"Among 827 participants who had a completed pregnancy, the pregnancy resulted in a live birth in 712 (86.1%), in a spontaneous abortion in 104 (12.6%), in stillbirth in 1 (0.1%), and in other outcomes (induced abortion and ectopic pregnancy) in 10 (1.2%)."

104 Spontanious abortions occurred during the study (12.6% of participants)

On average, 2-4% of completed pregnancies end in SA before 13 weeks gestation and <1% end in SA after 13 weeks gestation. 12.6% SA rate for participants 12 weeksG+ seems like an alarming number … Is there something i'm missing? 

"A total of 96 of 104 spontaneous abortions (92.3%) occurred before 13 weeks of gestation. No denominator was available to calculate a risk estimate for spontaneous abortions, because at the time of this report, follow-up through 20 weeks was not yet available for 905 of the 1224 participants vaccinated within 30 days before the first day of the last menstrual period or in the first trimester. Furthermore, any risk estimate would need to account for gestational week–specific risk of spontaneous abortion."

Of the 724 live born infants there were 12 sets of multiples.  

They account for roughly 3.3% of the live births in this study - Which aligns with the chances of conceiving multiples during fertility treatment. Naturally, the odds of having twins is about 1 in 250.  Leading me to believe some participants were seeing fertility specialists, meaning they had access to premium Healthcare. (My skepticism is also backed by the fact 94% of participants were healthcare personel.) It is more than likely these births make up the premature / underweight stats, correct?

"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. Data on neonatal outcomes are based on 724 live-born infants, including 12 sets of multiples."

"The registry enrolled 3958 participants with vaccination from December 14, 2020, to February 28, 2021, of whom 3719 (94.0%) identified as health care personnel."

Results not matched with relevant information collected throughout the study.

12.6% SA is very high, how can risk be accurately assessed without cross referencing data?  Why was so much data listed on the symptom report charts, but not applied to the reported outcome chart?

"The populations from which these rates are derived are not matched to the current study population for age, race and ethnic group, or other demographic and clinical factors."

Major Congenial Anomalies seen in 3% of live births. 

Shouldn't the major congenial anomalies be listed in the case study? Also, why were they not reported to VAERS?

"Values include only major congenital anomalies in accordance with the Metropolitan Atlanta Congenital Defects Program 6-Digit Code Defect List (www.cdc.gov/ncbddd/birthdefects/macdp.html. opens in new tab); all pregnancies with major congenital anomalies were exposed to Covid-19 vaccines only in the third trimester of pregnancy (i.e., well after the period of organogenesis)."

"No congenital anomalies were reported to the VAERS, a requirement under the EUAs."

"Who reported pregnancy-related adverse events were spontaneous abortion (46 cases; 37 in the first trimester, 2 in the second trimester, and 7 in which the trimester was unknown or not reported), followed by stillbirth, premature rupture of membranes, and vaginal bleeding, with 3 reports for each. No congenital anomalies were reported to the VAERS, a requirement under the EUAs."