An article by the website Daily Expose, shared on Facebook and Instagram, claims the US Centre for Disease Control and Prevention (CDC) grossly underreported miscarriage figures found in a study on Covid-19 vaccine safety during pregnancy.
However, this is misleading, as it ignores much of the relevant data and therefore totally contradicts the study’s conclusions.
The study examined the records of 827 respondents who had been given a Covid-19 vaccine and had a completed pregnancy, which means the pregnancy had ended in a live birth, spontaneous or induced abortion, stillbirth or ectopic pregnancy.
It found that 13.9% of those respondents reported a pregnancy loss, of which 12.6% were miscarriages.
The study found these rates were within a normal range, and that the preliminary findings did not show “obvious safety signals” among respondents who received mRNA Covid-19 vaccines.
However, the Daily Expose claimed the 12.6% miscarriage figure was incorrect because the majority of respondents were vaccinated during the third trimester, when it is “impossible to suffer a miscarriage”.
The article claims the true miscarriage rate was 82%. This was calculated by excluding all 700 participants who had live births who were vaccinated in their third trimester. This left 127 people who received the vaccine in the first two trimesters, 104 of whom (82%) had miscarriages.
This argument is incredibly misleading.
Dividing the number of people who had miscarriages by the number who had completed pregnancies and were vaccinated in the first or second trimester does not give the miscarriage rate in the first and second trimester.
Gynaecologist Dr Jen Gunter wrote in a newsletter: “Of course when you remove those 700 pregnancies the miscarriage rate looks artificially high, because the only way a person got into the data set...was if the pregnancy had ended and they had been vaccinated.”
To calculate the actual miscarriage rate for those vaccinated in the first and second trimesters, you’d need to divide the number of miscarriages by the total number of completed pregnancies of those who were vaccinated before 26 weeks. But we don’t have that total yet because most of those people are still pregnant.
As was noted in the study, the majority of participants from the v-safe registry who were vaccinated in their first and second trimesters had not given birth or otherwise by the time of the study’s publication. Having complete data from more of this cohort would have given the study greater balance and a better picture of outcomes across all pregnancies.
The claim that it’s “impossible” to have a miscarriage in the third trimester is only correct in a sense. A miscarriage is commonly defined as the loss of a pregnancy before 24 weeks of gestation (just before the end of the second trimester). Losing a pregnancy in the third trimester is possible, but is known as stillbirth (one was recorded in the study).
It is worth noting the relatively high incidence of miscarriage in pregnancy across all groups, with as many as 250,000 people in the UK every year sadly losing their pregnancy, accounting for one in five pregnancies.
While the researchers said the data did not indicate “obvious safety signals” they concede “more longitudinal follow-up, including follow-up of large numbers of women vaccinated earlier in pregnancy, is necessary”.
The study also looked at some benefits of vaccination, citing new evidence that shows vaccination in the third trimester leads to the transfer of Covid antibodies from mother to foetus during pregnancy, suggesting vaccines can help protect newborns too.
The Medicines and Healthcare products Regulatory Agency (MHRA) has previously stated there is no evidence to suggest the number of miscarriages reported in the UK following vaccination falls outside the normal range for miscarriages in general.
Advice from the NHS says the Pfizer/BioNTech and Moderna vaccines have been “widely used during pregnancy in other countries and no safety concerns have been identified.” Evidence reviewed by the MHRA “has raised no specific concerns for safety in pregnancy”.
We have checked multiple misleading claims about the relationship between vaccines and pregnancy, including that “vaccine shedding” can cause miscarriage and that the vaccines have caused 172 miscarriages since January.