Does the Flu Vaccine Really Increase Your Miscarriage Risk?

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Last fall, a study was published that hinted at a possible connection between the flu vaccine and miscarriage. Obviously, it’s troubling information. And doctors and health officials were right to address it. But it can also potentially add to the vaccine hysteria we find ourselves battling (STILL) when it comes to flu shots and other lifesaving vaccines. It’s important to educate yourself on the possible (very unlikely, but still possible) connection between getting the flu shot and suffering a miscarriage. It’s also important to have all the information available to make an informed decision.

So, what is the connection between the flu vaccine and miscarriage?

The study, funded by the Centers for Disease Control and Prevention, looked at the possibility of a link between certain versions of the flu vaccine and the risk of miscarriage. It’s important to note that the research is very preliminary, but researchers felt it was important for pregnant women to be made aware. The research is ongoing, but early findings suggest an association between repeat influenza vaccination and the risk of miscarriage. An association is not causation, but again, the more information we have, the better.

The study found that the risk of miscarriage in women who’d received the same version of flu vaccine two years in a row was slightly higher.

The flu vaccines in 2010-2011 and 2011-2012 were the same version, H1N1pdm09. This version was created following the deadly outbreak of H1N1 swine flu pandemic in 2009 that killed hundreds of thousands of people around the world. A similar study was conducted during the 2005-2006 and 2006-2007 flu seasons, and no link was found. But prior to 2009, the components of the flu vaccine were different. Researchers compared 485 pregnant women between the ages of 18 – 44 who had a miscarriage, and 485 pregnant women in the same age group who had normal deliveries during flu seasons 2010-2011 and 2011-2012.

Out of the 485 women who miscarried, 17 had gotten the flu vaccine within 28 days prior to their miscarriage. Those 17 women had also gotten the vaccine the year before.

Of the women who had normal deliveries, 4 were vaccinated two years in a row. Epidemiologist James Donahue said, “We only saw the link between vaccination and miscarriage if they had been vaccinated in the season before.” The study did have several limitations, including the sample size and the small number of women who’d miscarried and women who’d gotten the vaccine two years in a row. And remember, this study only covers the flu vaccine in 2010-2011 and 2011-2012, when the components of the vaccine had changed (but remained the same for the two years researchers studied). Additionally, miscarriages in the first trimester (when most of the miscarriages in the study occurred) are commonplace, so it’s hard to know if those in the study were linked in any way to the vaccine.

Health officials are urging that people not get overly alarmed by these findings, however. Plenty of medical research tells us the flu shot is safe during pregnancy. It is also potentially lifesaving.

Influenza during pregnancy can often be much more severe for the mother. It can also cause problems with the developing fetus, like birth defects and miscarriage. In addition, a vaccinated mother is the best protection against an infant has against the flu. It’s not recommended that babies under 6 months be given the flu shot. This year’s flu is particularly brutal, and it’s so important to protect yourselves when and where you can.

The CDC still recommends pregnant women get the flu shot at any stage of pregnancy. But they advise women to talk to their doctors about the latest information and timing of the vaccine. Another study regarding the flu vaccine and miscarriage is currently underway, for flu seasons 2012-2013 and 2014-2015. Those results are expected sometime in 2018 – 2019.

(Image: iStock/Jovanmandic)