A new study examining the potential effects of the flu vaccine during pregnancy showed an association between the vaccine and early-term miscarriage, but the American Congress of Obstetricians and Gynecologists (ACOG) still recommends that women receive the flu shot during pregnancy.
The study was a follow-up to a similar one that found no correlation between the flu shot and spontaneous abortion of pregnancy. Both were conducted by the same team of researchers, but the earlier study was conducted before the H1N1 epidemic of 2009, and the flu vaccine since has been re-engineered.
The earlier study was conducted during the flu seasons of 2005-07. The more-recent research took place in 2010-2012.
While researchers did find what they called an association between the flu vaccine and miscarriage, they emphasized that they could not establish a causal relationship between them.
The ACOG responded to the new study by releasing a statement encouraging pregnant women to continue to receive the flu vaccine as part of their prenatal care.
The statement is credited to ACOG President Haywood L. Brown and reads, in part:
“ACOG continues to recommend that all women receive the influenza vaccine. This is particularly important during pregnancy. Influenza vaccination is an essential element of prenatal care because pregnant women are at an increased risk of serious illness and mortality due to influenza. In addition, maternal vaccination is the most effective strategy to protect newborns because the vaccine is not approved for use in infants younger than six months.”
Study co-author Edward Belongia, director of the center for clinical epidemiology and population health at Wisconsin’s Marshfield Clinic, told National Public Radio that even though there was no causal relationship established between the vaccine and miscarriage, the researchers considered themselves obligated to report their findings.
Belongia also said the topic “clearly measures further investigation.”
The ACOG and the Centers for Disease Control (CDC) provide detailed information about health concerns for pregnant women, including vaccines, on their websites.
The ACOG emphasizes the potential dangers of influenza for pregnant women and unborn babies. It recommends that pregnant women be administered the inactivated flu vaccine, rather than the live flu vaccine.
Since 2010, the CDC has recommended flu vaccines for everyone aged 6 months and older – especially those considered at high risk for developing flu-related complications. The high-risk list includes:
- Pregnant women
- Children 5 and younger
- Adults 65 and older
- Nursing-home and long-term care facility residents
- Native Americans and Native Alaskans
- People diagnosed with asthma, chronic lung disease, heart disease, blood disorders, diabetes and other endocrine disorders, kidney disorders, liver disorders, HIV or AIDS and/or cancer
The CDC notes that there is no recommendation “for pregnant women or people with pre-existing medical conditions to get special permission or written consent from their doctor or health care professional for influenza vaccination” administered at a location outside their physician’s office.
The only people the CDC recommends receive no flu vaccine are infants 6 months or younger, and people with “severe, life-threatening allergies to flu vaccine or any ingredient in the vaccine.”
The CDC also recommends a preliminary conversation with a physician for people with an allergy to eggs and for people who have been diagnosed with Guillain-Barré Syndrome.