Preventing the flu
Getting the flu vaccine is the best step a pregnant woman can take to protect herself and her baby, Theiler said. [6 Flu Vaccine Myths]
In 2014, researchers at Dalhousie University in Nova Scotia found, after controlling for other factors, that getting the flu vaccine during pregnancy reduced the risk of preterm birth or giving birth to a low-birth-weight infant. The same New England Journal of Medicine study that found an increased risk of fetal death with flu infection during pregnancy also found that the flu vaccine was very effective, reducing the risk of flu during pregnancy by 70 percent.
Evidence also suggests that the flu vaccine is very safe during pregnancy. A study published Nov. 29 in the journal JAMA Pediatrics looked at a large registry of patients with Kaiser Permanente Northern California and found no evidence that the flu vaccine (or the flu) increased the risk of autism in children.
Nor have researchers found evidence of a heightened risk of adverse effects from the vaccine in pregnant women. A 2011 study in the American Journal of Obstetrics & Gynecology, for example, examined reports submitted to the Vaccines Adverse Event Reporting System, a federal system used to collect information about negative reactions to vaccines. Reports in the database do not have to be confirmed by doctors to be included. The study found no evidence of unusual patterns of adverse events during pregnancy or in infants, the researchers wrote.
Direct comparisons turn up similar results. A 2013 study in the journal Obstetrics & Gynecology compared nearly 76,000 women who received the flu vaccine during pregnancy with almost 150,000 women who didn't and found no increase in adverse effects among the vaccinated women. Another study in the same journal that year used similar data and found no additional risk from vaccination for common pregnancy complications such as high blood pressure, morning sickness or pulmonary embolism.
Handwashing is the most effective hygiene measure to prevent the flu, Theiler said. Still, if a pregnant women is in close contact with an infected individual — say, an older child — she should call her doctor right away, rather than just relying on handwashing, Theiler added. If the seasonal flu strain isn't well-covered by that year's vaccine, many physicians might want to preemptively treat the woman with anti-viral drugs to ensure she doesn't get sick, because the consequences of infection can be dire, Theiler said.
Any pregnant woman who experiences flu symptoms should call her doctor right away, Theiler said.
"They shouldn't wait it out at home or tough it out like they might do if they weren't pregnant," Theiler said. Again, anti-viral drugs would be the treatment of choice.
The bottom line, Theiler said, is that the flu is a "very bad thing for maternal mortality that's easy for us to prevent." In 2009, she said, the H1N1 epidemic increased the rate of deaths among pregnant women. That rate is typically very stable, Theiler said.
The rate of deaths "noticeably" increased just because of the flu, she said, "so that's a scary thing for us."
