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News • Pregnancy in pandemic times

Does the Covid-19 vaccine increase miscarriage risk? Study says no

There is no evidence of higher risk of miscarriage or ectopic pregnancy following vaccination against Covid-19 or infection with the disease, according to a new study.

The results, which have been published in the journal Nature Communications, bolster previous findings that Covid-19 vaccines are safe to have before and during pregnancy, experts say. Researchers from the University of Edinburgh and Public Health Scotland analysed data from more than half a million pregnancies in Scotland – 24.1% were during the pandemic, with the rest from the pre-pandemic period. 

This study provides reassurance that Covid-19 vaccines are safe in early pregnancy

Sarah Stock

Some 18,780 women were vaccinated just before conception or in early pregnancy, 9.1% of whom had a miscarriage. This compares with a 9.9% miscarriage rate for unvaccinated women pre-pandemic and 10 per cent for unvaccinated women during the pandemic. Some 3,025 women had a confirmed SARS-CoV-2 infection during the same period in pregnancy – the team did not find any evidence that women are at higher risk of miscarriage after being infected. 

The team also did not find any evidence that either vaccines or infections increase the risk of an ectopic pregnancy – when a fertilised egg implants itself outside the womb and fails to proceed to a full pregnancy. In the 10,570 women who had a vaccine in the early days of pregnancy, 1.2% had an ectopic pregnancy. This compares to 1.2% for unvaccinated women pre-pandemic and 1.1% for unvaccinated women during the pandemic. The Pfizer-BioNTech Covid-19 vaccine was the most commonly received vaccine by pregnant women in Scotland.  

These findings are part of the COPS study, which tracks levels of Covid-19 infection and vaccine uptake in pregnant women in Scotland, and conducts rigorous analyses including assessing the safety of vaccination in pregnancy. COPS is an offshoot of the EAVE II project, which uses anonymised linked patient data in Scotland to track the pandemic and the vaccine roll out in real time. This work was funded by Wellcome and the charity Tommy’s and supported by the charity Sands. "This study provides reassurance that Covid-19 vaccines are safe in early pregnancy," commented Professor Sarah Stock, COPS co-lead at University of Edinburgh’s Usher Institute and consultant obstetrician. 

Source: University of Edinburgh


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