We have been asked on WhatsApp why there appears to be a discrepancy between information on Pfizer’s website and patient information leaflet, and the official government advice for pregnant women thinking about getting the Covid-19 vaccine.
We have also seen comments on social media indicating that Pfizer has said there is insufficient data regarding the vaccine in pregnancy.
These claims appear to come from information in a February 2021 press release on Pfizer’s website about trials to evaluate its Covid-19 vaccine for pregnant women, part of which reads: “Available data on Pfizer-BioNTech Covid-19 Vaccine administered to pregnant women are insufficient to inform vaccine-associated risks in pregnancy.”
The patient information leaflet for the Pfizer/BioNTech vaccine, published online by the Medicines & Healthcare products Regulatory Agency (MHRA), says: “If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before you receive this vaccine.”
However, the Joint Committee on Vaccination and Immunisation (JCVI) has advised that pregnant women in the UK should be offered Covid-19 vaccines at the same time as people in the same age or risk group.
The Pfizer/BioNTech and Moderna Covid-19 vaccines are currently the preferred option for pregnant women.
What’s the evidence that the vaccine is safe for pregnant women?
As we have written before, pregnant women were excluded from the initial large-scale Covid-19 vaccine trials. There were 57 unintended pregnancies during the trials, but the number of cases was so small that they can’t be extrapolated in a meaningful way to the rest of the population.
However, there have been studies of different data sets from women who were vaccinated in pregnancy as part of the general roll out, with the aim of identifying any problems or safety concerns either in pregnancy or after birth. The results have been compared against the usual rate at which issues(such as miscarriage or preterm birth) would sadly normally be expected in populations of women who have not receievd a Covid-19 vaccine. One study also compared women vaccinated in pregnancy against women who had a Covid-19 infection during pregnancy.
From these, no significant safety concerns have arisen.
At the time of writing, almost 162,000 women in America who reported they were pregnant have been vaccinated, and more than 81,000 women in England (correct as of 31 August 2021) who reported that they were pregnant or could be pregnant at the time of vaccination have received at least one dose of vaccine.
In April, Public Health England said the fact that a large number of women in the USA had been vaccinated with Pfizer and Moderna vaccines without any safety concerns being identified meant that these were the preferred vaccines for women to have.
What have Pfizer and other experts said?
When Full Fact asked Pfizer about why there is information on its website indicating that there is insufficient data to inform the safe use of Covid-19 vaccines in pregnant women, a spokesperson confirmed that Pfizer was unable to say, within its remit, that there was enough evidence to support their use as it had not yet completed a large-scale clinical trial in pregnant women.
The spokesperson also said that, under rules set out by the US Food and Drug Administration, Pfizercarried out animal trials prior to enrolling women of childbearing potential who weren’t actively avoiding pregnancy and pregnant women in studies. Animal trials showed no evidence of fertility or reproductive toxicity in animals.
The spokesperson confirmed that the decision to vaccinate pregnant women was the responsibility of each individual country’s regulatory body using available information such as animal studies and real world data.
A spokesperson for the MHRA told Full Fact: “The MHRA closely monitors the safety of Covid-19 vaccine exposures in pregnancy, including Yellow Card reports for Covid-19 vaccines used in pregnancy.
“Pregnant women have the same risk of getting Covid-19 as non-pregnant women but they may be at an increased risk of becoming severely ill, particularly if they get infected in the third trimester or if they also have underlying medical problems, compared to non-pregnant women.
“The current advice of the JCVI is that the Covid-19 vaccines should be offered to those who are pregnant at the same time as non-pregnant individuals based on their age and clinical risk group. The Pfizer/BioNTech and Moderna vaccines are currently the preferred vaccines for use during pregnancy.
“Like most vaccines and medicines, clinical trials of Covid-19 vaccine in pregnant women were not carried out prior to use of the vaccines in the general population. However, evidence from non-clinical studies of the Covid-19 vaccines available in the UK have not raised any concerns about safety in pregnancy.
“Extensive international experience for the Pfizer/BioNTech Vaccine and Covid-19 Vaccine Moderna used in pregnancy have also not raised any safety concerns. The MHRA will continue to closely monitor safety data for use of the Covid-19 vaccines in pregnancy, including through evaluation of electronic healthcare record data.”
The information included in this article contains the latest evidence and official guidance available at the time it was written. This is not a substitute for medical advice. If you require specific medical advice please consult your GP or midwife.