Pregnant women can decide whether to receive the COVID-19 vaccine; safety monitoring suggests that COVID-19 vaccines don’t pose any specific risk for pregnant women
COVID-19 vaccines authorized for emergency use by the U.S. Food and Drug Administration demonstrated a high level of safety and efficacy in clinical trials. However, limited data is available regarding the safety and efficacy of these vaccines in pregnant women because they were excluded from initial clinical trials. Available evidence from animal studies and ongoing vaccine safety monitoring suggests that COVID-19 vaccines don't pose any specific risk for pregnant women. In contrast, pregnant women have an increased risk of suffering complications from COVID-19, which may affect pregnancy outcomes.
Inaccurate: Pregnant women can choose whether or not to receive the COVID-19 vaccine. No public health authority is “pushing” pregnant women to receive the COVID-19 vaccine.
Unsupported: There is no support for the claim that COVID-19 vaccines pose a danger to pregnant women. On the contrary, safety monitoring data so far indicates that COVID-19 vaccines don’t increase the incidence of adverse events in pregnant women compared to unvaccinated pregnant women.
On 23 February 2021, Children’s Health Defense published an article claiming that “public health officials push pregnant women to get COVID-19 shots, despite known risks”. The article received more than 7,000 interactions on Facebook and Twitter, according to social media analytics tool CrowdTangle. Children’s Health Defense, an organization that opposes vaccines, has propagated false claims about several health topics in the past.
The rollout of COVID-19 vaccines worldwide led to the spread of unsupported claims on social media about serious adverse events purportedly caused by the vaccine, like facial paralysis and deaths. In early February 2021, similarly unfounded claims that COVID-19 vaccines caused miscarriages and stillbirths in pregnant women went viral on Facebook. Children’s Health Defense recently repeated these claims in an article and further claimed that health authorities are “pushing” pregnant women to receive a COVID-19 vaccine that has caused dozens of miscarriages and preterm births.
The article based these claims on the number of pregnancy-related adverse events reported to the U.S. Vaccine Adverse Events Reporting System (VAERS) after COVID-19 vaccination. This is a misuse of VAERS reports, as Health Feedback explained in this earlier review. VAERS collects reports on adverse events, which describe any health problems that happen after vaccination, whether or not they are related to the vaccine. VAERS is a useful surveillance platform to detect signals that may highlight potential vaccine safety concerns. However, the reports alone don’t demonstrate that the vaccine caused the adverse event.
Anyone can report an adverse event to VAERS, including healthcare professionals, vaccine manufacturers, and the general public, regardless of whether they believe the vaccine caused the event. Reporting of a miscarriage following COVID-19 vaccination doesn’t prove that the vaccine caused it, especially given the fact that miscarriage is not uncommon. Estimates indicate that about 10 to 15 percent of known pregnancies end in miscarriage, but the causes often aren’t identified.
So far, three COVID-19 vaccines are authorized for emergency use by the U.S. Food and Drug Administration (FDA), including one by Pfizer and BioNTech and another by Moderna. On 27 February 2021, the single-dose vaccine by Johnson & Johnson became the third COVID-19 vaccine to receive emergency use authorization after a favorable analysis by the FDA. Several stages of clinical trials conducted in tens of thousands of participants as well as monitoring of ongoing vaccination showed that these vaccines are safe and protect against COVID-19 with a high efficacy[1-3]. In contrast, available data on the vaccines’ safety and efficacy in pregnant women are limited as the initial round of clinical trials excluded them.
Contrary to what the article claimed, the exclusion of pregnant women from clinical trials is primarily due to the close follow-ups required during pregnancy and after delivery, which causes licensure delays. Consequently, vaccine manufacturers tend to exclude pregnant women from clinical trials, depriving this group of specific safety and efficacy assessment. However, this is about to change for COVID-19 vaccines. On 18 February 2021, Pfizer launched the first clinical trial to evaluate COVID-19 vaccine safety and efficacy in 4,000 pregnant women, involving a follow-up of seven to ten months.
Children’s Health Defense incorrectly attributes this exclusion of pregnant and lactating women from clinical trials to lack of vaccine safety. This idea comes from the historical assumption that exposing a fetus to an experimental drug was unethical. This practice created a profound knowledge gap about the safety and efficacy of medications during pregnancy, forcing pregnant women to make real-time decisions based on little or no scientific evidence. In 2016, the 21st Century Cures Act established the Task Force on Research Specific to Pregnant Women and Lactating Women to overcome this limitation and advise on how to safely and ethically include this population in clinical research.
As a general rule, vaccine recommendations for pregnant women exclude vaccines containing live viruses due to the potential risks to the fetus. COVID-19 vaccines don’t contain live viruses. Scientific evidence also indicates that certain vaccines are safe, effective, and even necessary during pregnancy. Currently, the U.S. Centers for Disease Control and Prevention (CDC) routinely recommends that pregnant women receive the flu and pertussis (whooping cough) vaccines, because flu and pertussis can cause severe complications in newborns.
Although pregnant women are generally excluded from clinical trials, 23 participants (12 in the vaccine and 11 in the placebo group) in the Pfizer-BioNTech trial, and 13 participants (6 in the vaccine and 7 in the placebo group) in the Moderna trial became pregnant during the course of the clinical trial. Spontaneous abortion and miscarriage occurred in two participants of the Pfizer-BioNTech trial and one participant of the Moderna trial, all of them in the unvaccinated placebo group.
Although the number of pregnancies in the clinical trials is too small to provide conclusive evidence about the vaccine’s safety, additional data from laboratory animals and safety monitoring of ongoing COVID-19 vaccination in pregnant women are reassuring. Vaccinated women didn’t show an increased risk of miscarriage and stillbirths compared to unvaccinated pregnant women. Therefore, there is currently no evidence to support the claim that the potential risks of COVID-19 vaccination outweigh the benefits in pregnant women. In contrast, pregnant women are more likely to develop severe illness from COVID-19, which may also impact pregnancy outcomes.
The scarcity of safety data in pregnant women led public health authorities to issue mixed guidance about COVID-19 vaccination for this group. However, none of these recommendations can be interpreted as “pushing” pregnant women to receive the COVID-19 vaccine, as the Children’s Health Defense article claimed. For example, the World Health Organization (WHO) recommended that pregnant women don’t receive the vaccine unless they are at high risk of COVID-19 exposure or chronic conditions.
Considering the higher risk of complications from COVID-19 in pregnant women, the CDC stated that “people who are pregnant and part of a group recommended to receive the COVID-19 vaccine may choose to be vaccinated”. For the same reason, The American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) released a joint statement stressing that COVID-19 vaccines “should not be withheld from pregnant individuals who choose to receive the vaccine”. Rather than “pushing” COVID-19 vaccines on pregnant women, these recommendations indicate that vaccination is a personal choice.
The article also made a series of previously debunked allegations about the dangers of COVID-19 vaccines and vaccines in general. One of these claims is that COVID-19 vaccines will cause sterility in women due to autoimmune responses. This claim is based on the alleged similarity between the sequences of the SARS-CoV-2 Spike protein and the human placenta protein syncytin-1. As Health Feedback explained in this previous review, the similarity between both proteins is minimal and occurs in many other proteins. Therefore, it is extremely unlikely that COVID-19 vaccines trigger autoimmune responses against placentas. In fact, there is no evidence of such effects in women who were infected with COVID-19 or vaccinated against the disease.
Finally, the Children’s Health Defense article repeated the baseless claims that vaccine ingredients are toxic and linked to autism or poorer health outcomes in children. Vaccine candidates are rigorously tested for safety during clinical trials and continuously monitored after approval.
As Health Feedback explained in this earlier review, large-scale studies didn’t find a greater incidence of adverse health outcomes in vaccinated children compared to unvaccinated children. Numerous studies also demonstrated that vaccine ingredients are safe at the levels present in vaccines and don’t cause autism, as explained in this Insight article and this review by Health Feedback. Based on a review of the literature, the U.S. National Academies of Sciences, Engineering, and Medicine and the Vaccine Education Center at the Children’s Hospital of Philadelphia both concluded that vaccines don’t cause autism.
In summary, current evidence doesn’t support the claim that COVID-19 vaccines pose a specific risk for pregnant women. Although available data from clinical trials is limited, safety monitoring of ongoing vaccination campaigns shows that COVID-19 vaccines don’t increase the risk of pregnancy-related adverse events compared to unvaccinated pregnant women. Instead, the vaccines might protect pregnant women from an increased risk of severe illness and adverse pregnancy outcomes resulting from natural COVID-19 infections. Pregnant women can choose whether or not to receive COVID-19 vaccines and aren’t being “pushed” to take the vaccine by public health authorities.
- 1 – Polack et al. Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine. New England Journal of Medicine.
- 2 – Baden et al. (2020) Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine. New England Journal of Medicine.
- 3 – Gee et al. (2021) First Month of COVID-19 Vaccine Safety Monitoring — United States. Morbidity and Mortality Weekly Report.
- 4 – Blehar et al. (2013) Enrolling Pregnant Women: Issues in Clinical Research. Women’s Health Issues.