Review of data on COVID vaccines and pregnant women suggests there is no increased risk of miscarriage

A team of reproductive specialists from Queens Medical Research Institute, Imperial College London and University College London, all in the UK, have conducted a systematic review and associated meta-analysis of data on pregnant women receiving COVID vaccines. In their paper published in the journal human reproduction, the team reports that they found no increased risk of miscarriage in women who received any of the COVID vaccines.

From the beginning of the pandemic, shortly after COVID vaccines became available, there have been concerns about possible negative associations among pregnant women who were vaccinated. Such concerns were initially raised because little to no research was done on the vaccine’s impact on pregnant women, as the vaccine was being rushed to a needy population. As the pandemic progressed, concerns continued to be raised about a possible increased risk of miscarriage.

As time went on, medical scientists noticed that worldwide pregnancies and births decreased during the pandemic, although it was not known why. Some studies suggested that people simply chose not to have a baby during a pandemic – others suggested it showed that medical scientists were either not doing their jobs or were outright lying about findings related to vaccinating pregnant women. In this new effort, the team in the UK tried to find the answer to at least part of the debate: do COVID vaccines increase the risk of miscarriage?

The researchers combed data from EMBASE, MEDLINE and Cochrane CENTRAL, looked at statistics from before the start of the pandemic through June 2022, and compared miscarriage rates between pregnant women who received a COVID vaccine and those who did not. In total, they followed the pregnancies of 149,685 women.

They found an overall average miscarriage rate of 9% for women who received any of the available vaccines – a rate that is not statistically significant when compared to that of pregnant women who did not receive a vaccine. They also found no significant differences in the number of live births for the same women in the study.

The research team acknowledges that the heterogeneity observed across the studies they reviewed, along with patient characteristics and risk bias, suggests that some of the data quality did not meet scientific standards. So they suggest that more work is needed to confirm their results.

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