[FALSE] Is there a 92.3% spontaneous abortion rate among those who receive an mRNA COVID-19 vaccine before 13 weeks of gestation?

 

Screenshot of the Facebook post.

 

The Claim and Our Verdict

• The claim: A Facebook post published Nov. 25, 2021 claims that the rate of spontaneous abortion is 92.3% among those who have received an mRNA COVID-19 vaccine before 13 weeks of gestation.
• Fact-checking:
  • The claim misinterpreted the data in the study. The 92.3% rate refers to the proportion of spontaneous abortions before 13 weeks of gestation compared to the total spontaneous abortion cases in the study. It does not refer to the probability of spontaneous abortion among those who have received an mRNA COVID-19 vaccine before 13 weeks of gestation.
  • The Facebook post also claims that the study’s finding should be amended, as “81.9% of those who have spontaneous abortions took the vaccine before the 20^th week of gestation.” In fact, the claim wrongly calculated the rate. A spokesperson from U.S. Centers for Disease Control and Prevention (CDC), the institute that the paper’s authors were affiliated with, told HKBU Fact Check: “Using an alternative method, we have calculated that there are 27 (2.0%) spontaneous abortions among 1,364 participants vaccinated at less than 20 weeks gestation who were at least 20 weeks gestation on March 30th (the date of the data used for the report).”
  • Moreover, the claim overlooks the population-based background incidence rate of spontaneous abortion. Dr. Guan Jing, vice president of the International Society for Reproductive Surgery and Fallopian tube (ISRS), president of the China office of ISRS, and director of the Center for Reproductive Medicine at Peking University People’s Hospital, told HKBU Fact Check, “In fact, the population-based background incidence rate of spontaneous abortion within the first 13 weeks of gestion is 10%-15%.”
  • The claim also wrongly translated the study. The sentence in the study, “Preliminary findings did not show obvious safety signals among pregnant persons who received mRNA COVID-19 vaccine” indicates that the study did not find any safety signals for the pregnant females who were inoculated with the mRNA COVID-19 vaccines, not that the safety of mRNA vaccines is still unknown among the pregnant population, as purported in the claim.
  • The spokesperson from the CDC told HKBU Fact Check that there is growing evidence of the safety of COVID-19 vaccines during pregnancy, and the CDC strongly recommends COVID-19 vaccination either before or during pregnancy.
• Our ruling: We rate the claim as FALSE.

News Brief

A Facebook post published Nov. 25, 2021 claims that the rate of spontaneous abortion is 92.3% among those who have received an mRNA COVID-19 vaccine before 13 weeks of gestation. The traditional Chinese-language post translates as: “Recently, there have been many news stories about stillbirths and miscarriages in pregnant women after vaccination. Six months ago, I found a study which suggested an extremely high risk among those vaccinated pregnant females. It shows that a pregnant woman who receives the vaccine will inevitably miscarry.”

The Nov. 25 post included a screenshot of another Facebook post published July 16, 2021 by the same author. Th July 16 post translates as: “A study titled ‘Preliminary Findings of mRNA Covid-19 Vaccine Safety in Pregnant Persons’ was published June 21 in The New England Journal of Medicine. It states, ‘Preliminary findings did not show obvious safety signals among pregnant persons who received mRNA Covid-19 vaccines,’ indicating the safety of mRNA vaccines for pregnant females is still unknown.”

The July 16 post adds that the data provided in the study are incorrect. The post translates as: “The study states that a total of 827 participants had received an mRNA COVID-19 vaccine, while 700 of them received their first eligible dose in the third trimester. It indicates that 127 participants received the vaccine before the third trimester. After amending the denominator, the updated rate of spontaneous abortion before the 20^th week of gestation should be 81.9%, i.e., 100 participants received the mRNA vaccine before the third trimester, and 82 of them miscarried… The footnote of the table also states, ‘A total of 96 of 104 spontaneous abortions (92.3%) occurred before week 13 (the first trimester is from week 0 to week 13) of gestation.’ We can see from these results that pregnant women receive the vaccine in their early phase of gestation will be much more likely to miscarry. The earlier you receive the vaccine, the more likely you will miscarry.”

As of the issuance of this report, the Nov. 25 post had been shared 45 times, and it had received five comments and 158 likes or reactions.

Another post was shared Feb. 11, 2022 by the same author. The post translates as: “The previous study also shows that for those pregnant women who receive the Pfizer-BioNTech vaccine before the 13^th week of gestation, the possibility of spontaneous abortions is almost ninety percent.”

As of the issuance of this report, the Feb. 11 post had been shared 58 times, and it had received eight comments and 185 likes or reactions.

Fact-checking

The study mentioned in the claim was published June 17, 2021 and was amended Oct. 14, 2021. It was co-authored by members of the U.S. Centers for Disease Control (CDC) v-safe COVID-19 Pregnancy Registry Team.

1. The 92.3% rate in the study does not refer to the possibility of spontaneous abortion among pregnant women who receive the mRNA vaccine in the first 13 weeks of gestation.

The claim misinterpreted the data in the study. The 92.3% rate actually refers to the proportion of spontaneous abortions during the first 13 weeks of gestation compared to all participants who received the mRNA vaccine and had a completed pregnancy ending in a spontaneous abortion.

The study’s results show that as of March 30, 2021, the v-safe pregnancy registry enrolled 3958 participants with the mRNA COVID-19 vaccination from Dec. 14, 2020, to Feb. 28, 2021. The timing of receipt of the first vaccine dose was as follows:

Of the total participants who received the vaccine in the first or second trimester, initial data had been collected and follow-ups scheduled at designated time points approximately 10 to 12 weeks apart for 91.9% (1040/1132) of those who received a vaccine in the first trimester and 99.2% (1700/1714) who received a vaccine in the second trimester. Among 827 participants who had a completed pregnancy at the time of follow up, 104 pregnancies (12.6%) had resulted in spontaneous abortion. Among all the spontaneous abortions observed in this study, 92.3% (96/104) occurred in the first 13 weeks of gestation. The proportion, therefore, does not refer to the rate of spontaneous abortion among those who received the mRNA COVID-19 vaccine before 13 weeks of gestation.

2. The rate of spontaneous abortion among those who received the COVID-19 vaccine in the first 20 weeks of gestation was not 81.9%.

According to the second footnote in Table 4 of the study, among 827 participants who reported a completed pregnancy, 700 of them received their first eligible dose in the third trimester. Based on this, the claim states that 127 participants received their COVID-19 vaccination before the third trimester. The claim adds that by using 127 as the denominator and all cases of spontaneous abortion (104) as the numerator, the possibility of spontaneous abortion before the 20^th week of gestation among those who received the COVID-19 vaccination is 81.9%.

However, this is a miscalculation. The number 827 refers to the number of the participants who had a completed pregnancy, rather than the number of vaccinated participants. The number of participants who received the vaccine before the third trimester cannot be calculated by subtracting the number of those who received their first eligible dose in the third trimester from the number of all participants who had a completed pregnancy. Thus, the number 127 should not be the denominator to calculate the rate of spontaneous abortion.

Martha Sharan, spokesperson for the CDC, told HKBU Fact Check: “Using an alternative method, we have calculated that there are 27 (2.0%) spontaneous abortions among 1,364 participants vaccinated at less than 20 weeks gestation who were at least 20 weeks gestation on March 30th (the date of the data used for the report). This, however, is an underestimate of the true proportion, as we do not know that all 1,337 pregnancies (1,364 – 27) were ongoing on March 30th.”

3. The claim overlooked the population-based background incidence rate of spontaneous abortion.

Dr. Guan Jing, vice president of the International Society for Reproductive Surgery and Fallopian Tubes (ISRS), president of the China office of ISRS, and director of the Center for Reproductive Medicine at Peking University People’s Hospital, told HKBU Fact Check: “In fact, the population-based background incidence rate of spontaneous abortions within the first 13 weeks of gestions is 10%-15%. 80% of all spontaneous abortions occurred during the first 13 weeks of gestation.” The claim, therefore, did not take into account the background incidence rate of spontaneous abortions.

4. The claim wrongly translated the conclusion of the study

Concerning the sentence in the study, “Preliminary findings did not show obvious safety signals among pregnant persons who received mRNA COVID-19 vaccine,” the claim states that this means that the safety of mRNA vaccines is still unknown for pregnant women. However, this sentence actually indicates that the study did not find any safety signals for the pregnant females who were inoculated with mRNA COVID-19 vaccines.

The CDC team also told HKBU Fact Check that there is growing evidence of the safety of COVID-19 vaccines during pregnancy. The CDC also shared four research papers supporting this conclusion (paper 1, paper 2, paper 3, paper 4). The CDC team added, “On August 11, CDC recommended that pregnant people should be vaccinated against COVID-19. COVID-19 vaccination is recommended for all people 12 years and older, including people who are pregnant, breastfeeding, or trying to get pregnant now or might become pregnant in the future… Pregnancy increases the risk for severe illness from COVID-19. Pregnant people are more likely to be hospitalized, require critical care including ventilation and admission to the intense (intensive) care unit. In addition, COVID-19 during pregnancy increases the risk for preterm birth of the infants… The increased circulation of the highly contagious Delta variant, the low vaccine uptake among pregnant people, and the increased risk of severe illness and pregnancy complications related to COVID-19 infection among pregnant people make vaccination for this population more urgent than ever.”