Blogs and social media posts claim that data compiled in a study concludes that over 80% of pregnancies end in miscarriage after receiving the first dose of COVID-19 vaccines in the first or second trimester. The posts have taken figures from a table in a study published in the scientific journal “New England Journal of Medicine”, but used it out of context.
A headline posted by a popular blogpost reads: “Study data manipulated by CDC to show Covid-19 vaccines are safe for pregnant women when in fact 4 in 5 suffered a miscarriage (archive.is/rx72Z). "
The claim was also shared on another website (archive.is/kv6ly) with a headline: “BREAKING NEWS: RNA Vaccine Doses Caused Miscarriages in 82% of Women – REPORT REVEALS the Facts”.
Examples of similar claims made on social media:
https://www.facebook.com/photo.php?fbid=4661038570590240&set=a.310515865642554&type=3&theater
"I'm pregnant and I will never touch things! Don't mess with me or my baby," one person commented on Instagram.
The authors of the blog posts make a series of calculations based on Table 4 within a preliminary study published in the New England Journal of Medicine (NEJM) in 2020 (here).
However, the logic is flawed and the calculations are based on only a portion of the total who participated in the study.
The preliminary report used data collected through the Centers for Disease Control and Prevention (CDC), a credible registry that collects information from pregnant women who have received a Pfizer-BioNTech or Moderna COVID-19 vaccine (here).
A sample of 3,598 pregnant women who had received a COVID-19 vaccine was used by the study authors, who then conducted a follow-up two to three months later. Initial data had been collected and a limited number of follow-ups had been conducted by the time the preliminary study was published.
Of the 3,958 cases (pregnant women) included in the study, 827 had abortions.
Of the 827 women who had a completed pregnancy, 104 had a miscarriage. Therefore, the authors calculate that in the completed pregnancies, there was a miscarriage rate of 12.6%. (This was calculated only with those who had a full-term pregnancy by the time the previous study was published).
(Full article by Reuters in English)