Should pregnant women get the COVID-19 vaccine? WHO, CDC are at odds over guidance

More than 26 million doses of the Pfizer or Moderna COVID-19 vaccine have now been administered in the United States, but questions over who should be getting it first — and who should be avoiding it entirely — continue to circulate.

This week, the World Health Organization further muddied the waters with interim guidance stating that the vaccine is “currently not recommended” for pregnant women unless they are “at risk of high exposure.” The decision is at odds with that of the Centers for Disease Control and Prevention, which insists the vaccine is safe for pregnant women, saying it is “unlikely to pose a risk.”

Dr. Myra Wick, an obstetrician-gynecologist with the Mayo Clinic, says she is currently following the guidance of the American College of Obstetricians and Gynecologists (ACOG), which is holding firm in its stance that the vaccine should be offered to all pregnant women. Dr. Christopher Zahn, ACOG’s vice president of practice activities, tells Yahoo Life that the organization “remains steadfast in its guidance that both COVID-19 vaccines currently authorized by the FDA should be made available to pregnant individuals who choose to receive the vaccine.”

So why are the WHO and CDC at odds? Here’s what you need to know.

The World Health Organization says pregnant women should not get the vaccine unless they are at high risk of exposure. The Centers for Disease Control and Prevention disagrees. (Photo: Getty Images)
The World Health Organization says pregnant women should not get the vaccine unless they are at high risk of exposure. The Centers for Disease Control and Prevention and others disagree. (Photo: Getty Images)

The WHO isn’t recommending the vaccines for pregnant women due to a lack of data

In an email to Yahoo Life, a spokesperson for the WHO expanded on its stance, sharing a similar explanation for the Pfizer and Moderna vaccines. “The available data on mRNA vaccination of pregnant women are insufficient to assess vaccine efficacy or vaccine-associated risks in pregnancy,” the WHO wrote. “Further studies are planned in pregnant women in the coming months. As data from these studies become available, recommendations on vaccination will be updated accordingly.”

Despite requests from ACOG and others, pregnant women were not a part of either vaccine’s clinical trials. The WHO feels that until data on pregnant women is collected, getting the vaccine may — for many — be a choice that comes with more risks than benefits. “At this time, WHO does not recommend the vaccination of pregnant women,” WHO tells Yahoo Life. “This position will be reviewed and may evolve as more data becomes available.”

The CDC and ACOG disagree, noting that mRNA vaccines do not contain live virus

On its website, the CDC specifically states that “pregnant women may safely receive inactivated vaccines,” mentioning the flu shot and Tdap, a vaccine against pertussis, both of which Wick says are routinely and safely given. The organization notes that the type of vaccine being used is important. “While studies have not yet been done, experts believe mRNA vaccines like COVID-19 vaccines are unlikely to pose a risk for pregnant people,” the CDC wrote in a tweet on Dec. 29.

MRNA (short for messenger RNA) vaccines work by encoding the spike protein on the surface of SARS-CoV-2, the virus that causes COVID-19, and using it to trigger an immune response. Wick says this boosts her confidence about its safety. “Mechanistically, there isn’t any reason to think that they’re going to be harmful,” she says. “People worry about ‘Is it going to integrate into my genome?’ It’s not. It stays in the part of the cell where the DNA is not housed ... so mechanistically, it seems like it should be safe.”

Zahn and ACOG echo this sentiment. “Both the Pfizer-BioNTech and Moderna vaccines are not live-virus vaccines,” says Zahn. “They do not enter the nucleus and cannot cause any genetic changes. The safety of these vaccines was demonstrated in the clinical trials with non-pregnant individuals, and it is expected that there will be similar results in pregnant individuals.”

The vaccine has not been specifically tested on pregnant women, but they were present in the trials

Although neither Pfizer nor Moderna intentionally included pregnant women in its clinical trials, both companies ended up with more than a few. According to reports, 23 women in the Pfizer trial and 13 in the Moderna trial were either unknowingly pregnant at the time the trial began or became pregnant during it.

Of the pregnant women in the Pfizer trial, 12 got the vaccine and 11 the placebo. No pregnancy-related side effects were reported in the vaccine group, but two miscarriages occurred in the placebo group. Among the Moderna cohort, six of the pregnant women reportedly got the vaccine and seven received placebo. None of those who received the vaccine reported side effects regarding their pregnancy. In the placebo group, one woman experienced a miscarriage and another chose to get an abortion.

According to a report this week from the CDC, at least 15,000 pregnant women have received the vaccine thus far. The organization is closely tracking adverse effects but said the safety data that’s been collected so far is “reassuring and consistent with that observed from the pre-authorization clinical trials.”

The WHO’s stance is that, without data, the risks of the vaccine may outweigh the benefits

Central to the WHO’s new guidance, it seems, is the concept that in the absence of data, pregnant women may be putting themselves at risk. “WHO recommends not to use [the COVID-19 vaccine] in pregnancy, unless the benefit of vaccinating a pregnant woman outweighs the potential vaccine risks, such as in health workers at high risk of exposure and pregnant women with comorbidities placing them in a high-risk group for severe COVID-19,” the organization writes. “Information and, if possible, counseling on the lack of safety and efficacy data for pregnant women should be provided.”

The vaccine side effects that have been reported are not likely to be dangerous to pregnant women

It has now been well recorded that both the Pfizer and Moderna vaccines are likely to produce some temporary side effects — most commonly, pain, fatigue and headache. Experts say the reactions are a good sign, showing that the vaccine is “triggering an immune response.”

Ob-gyns pay close attention to these reactions, Wick says, but those being described aren’t a danger to pregnant women. “We worry about high fever, but most of the fevers that are being reported are low grade, and it’s safe to take Tylenol to help reduce fever in pregnancy,” she notes. “Most of the other side effects — muscle aches and headaches — they’re not pleasant, but they’re not harmful to mom or baby.”

Rather than concern about the risks of the vaccine, doctors and experts say the focus should be on the known dangers of COVID-19 during pregnancy

A study of more than 1,200 pregnant women released on Thursday from the Society for Maternal-Fetal Medicine found that pregnant individuals who experienced a severe case of the virus were more likely to die as a result of the infection, as well as more likely to experience pregnancy complications such as preterm birth, C-section, postpartum hemorrhage and high blood pressure.

Wick has treated patients like this firsthand, and for that reason suggests that all pregnant women talk to their health care provider about whether the vaccine is right for them. “Women who are pregnant and who contract COVID are at increased risk for needing to be hospitalized, needing ICU care, even needing to be intubated,” Wick says. “There’s definitely increased risk — especially for those who are at increased risk environmentally or have [health conditions] that might make them more vulnerable. They should consider vaccination, because we don’t have any reason to think it’s unsafe.”

Zahn agrees. “Each person must make the best decision for themselves, in conjunction with their clinical care team, when feasible, based on the information and data that is currently available,” he tells Yahoo Life. “For now, some may decide that the risks outweigh the benefits, but ACOG firmly believes that pregnant people deserve autonomy and must be given the choice to be vaccinated in the face of a potentially life-threatening virus and in the absence of credible data that would suggest it would do harm.”

For the latest coronavirus news and updates, follow along at According to experts, people over 60 and those who are immunocompromised continue to be the most at risk. If you have questions, please reference the CDC’s and WHO’s resource guides.