Are COVID-19 Vaccines Safe for Pregnant Women?

Disclaimer: This article represents a summary of recent literature but is in no way providing medical advice.

As COVID-19 vaccines become more widely available, pregnant women face a dilemma -- one of seemingly conflicting information. Until early February 2021, the WHO had advised against pregnant women taking the vaccine, quoting potential “vaccine risks”. The US Center for Disease Control and Prevention (CDC)’s latest official statement, on the other hand, provides that pregnant women who are healthcare or essential workers “may choose to be vaccinated”. Meanwhile, the American College of Obstetricians and Gynecologists (ACOG) state that COVID-19 vaccinations should not be withheld from pregnant women, and that women should discuss individual risks and benefits with their healthcare providers. What explains this controversy, and how should pregnant women move forward?

The issue lies in that there is a severe lack of data on the safety of COVID-19 vaccines for pregnant women. Following established norms, none of the major vaccine makers included pregnant women in their first clinical trials; indeed, an evaluation of international clinical trials conducted last spring, found that all nine global COVID-19 vaccine trials at the time listed pregnancy as an exclusion criterion. According to a WHO spokesperson, it was due to this lack of data, that the agency “could not provide a broad recommendation for vaccination of pregnant women”.

Despite these statements, many doctors are adamant that pregnant women should receive the vaccine. Their reasoning is that the threat of infection for pregnant women outweighs the as yet unproven dangers of the vaccine. Research from various groups around the world indicates that pregnant women with COVID-19 are at higher risk of hospitalization and severe disease in comparison to non-pregnant women. Indeed, an analysis of 77 cohort studies published last September, with data from more than 11,400 women with confirmed or suspected COVID-19, identified pregnant women as a high-risk group. According to the analysis, the likelihood of pregnant women with COVID-19 being admitted to the intensive-care unit (ICU) was 62% higher than for non-pregnant women, while the odds of needing invasive ventilation were 88% greater.

Behind these doctors opinions is also a significant body of literature indicating no harm to pregnant women or their children from inactivated vaccines. Doctors believe that this data is applicable to the Moderna and Pfizer vaccines, which, in being mRNA vaccines, are not made from a live virus. Rather, these vaccines instruct the body's cells how to build a protein fragment based on the SARS-COV-2 virus, which in turn triggers an immune response. Once this happens, "the cell breaks down and gets rid of the mRNA". Because the mRNa degrades so quickly, it is therefore unlikely to harm the mother or fetus.

While this information appears positive, “a direct extrapolation to COVID-19 vaccines should be avoided”. As Linda Eckert, a professor of obstetrics and gynecology at the University of Washington explains, “The challenge is that we don’t have a previous vaccine with the mRNA technology.” It is also not clear when during pregnancy it is best to be vaccinated. Fever is a known possible side effect of several COVID-19 vaccines, however, women must be generally wary of contracting a fever during pregnancy -- especially in the first trimester, when having a fever is associated with an increased risk of birth defects.

Making the decision of whether or not to vaccinate all the more complicated,  pregnant women who are vaccinated from the second trimester onward may be able to pass on some of the vaccine’s protection to their child. This is because the vaccine recipient at that stage of pregnancy is able to transfer antibodies through the placenta.

With so many facets of the disease and the vaccine being unknown, we at Maternova will be keeping a close watch on the literature. At the moment, the official WHO guideline is that pregnant women should decide for themselves in conference with their medical providers on the risks and benefits of vaccination. Under these circumstances, women who are working from home, for instance, and are able to mitigate their exposure, may opt to postpone vaccination until after delivery. By contrast, pregnant health care workers and their doctors may feel that they should receive the vaccine as soon as possible. A clear-cut answer will only be attainable once more research is disseminated and the risks of vaccination are ascertained.

Sources:

https://www.cnn.com/2021/01/29/health/pregnancy-covid-vaccine-wellness/index.html

https://www.scientificamerican.com/article/why-covid-vaccines-are-likely-safe-for-pregnant-people1/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7834417/#b0005

https://www.nature.com/articles/d41586-021-00578-y

 By Laila R.