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June 28 - July 4
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The mRNA vaccines present no danger for pregnant women
The first vaccines against SARS-CoV-2 to receive authorisation were both mRNA vaccines: Pfizer-BioNTech and Moderna. However, the first clinical studies carried out on these vaccines did not include pregnant women. Pregnancy does increase the risk of developing a severe form of COVID-19 and infection may also have adverse effects on gestation and the foetus. Researchers at the CDC (Centers for Disease Control and Prevention, Atlanta, USA) have therefore carried out checks on the safety of these mRNA vaccines for pregnant women.
The researchers used a system for monitoring any secondary effects after vaccination, and selected women in the States who had received 2 doses of an mRNA vaccine during pregnancy. The 3 958 women who enrolled in this study were vaccinated between December 2020 and February 2021.
Secondary effects following vaccination were similar overall to those experienced by women in general. Those who were pregnant more often reported pain at the injection site, but had less headaches, shivering or fever.
The scientists then looked at undesirable side effects on the pregnancy and on the new-born child (miscarriages, premature births, low birth weight or birth defects). They were thus able to ascertain that the level of undesirable side effects was the same as for the unvaccinated general population prior to COVID-19.
The results of this preliminary study on the safety of anti-SARS-CoV-2 mRNA vaccines on pregnant women do not highlight any specific risks for the women or for their new-born children. In addition, maternal antibodies, triggered after vaccination, seem to be transmitted to the unborn child through the placenta from the 3rd trimester of pregnancy onwards, giving the baby a certain level of protection against COVID-19.
