To get flu shots: Pregnant and postpartum women

Get ready to recommend flu vaccine to your pregnant and postpartum patients. According to the Centers for Disease Control and Prevention (CDC), less than one-fourth of pregnant women in the United States were vaccinated against seasonal influenza during the 2007-08 flu season.1

The Advisory Committee on Immunization Practices (ACIP) is recommending that pregnant and postpartum women receive the seasonal influenza vaccine this year, even if they received 2009 H1N1 or seasonal influenza vaccine last year. Manufacturers have informed the CDC that they expect to produce approximately 160 million doses of vaccine this year, so there should be a substantial supply to cover those who wish to receive it, including pregnant women, says Tom Skinner, a CDC spokesperson.

What flu viruses are included in the seasonal vaccine for the years 2010 and 2011? The World Health Organization (WHO) in Geneva, Switzerland, has recommended that the Northern Hemisphere's 2010 and 2011 seasonal influenza vaccine contain the following three vaccine viruses: an A/California/7/2009 (H1N1)–like virus, an A/Perth/16/2009 (H3N2)–like virus, and a B/Brisbane/60/2008–like virus. The Food and Drug Administration, which determines which viruses will be used in U.S.-manufactured vaccines, has selected the same vaccine viruses. The H1N1 virus that is recommended for inclusion in the current seasonal influenza vaccine is a pandemic 2009 H1N1 virus; it is the same vaccine virus as was used in the 2009 H1N1 monovalent vaccine.

Several medical groups, including the American College of Obstetricians and Gynecologists; the Association of Women's Health, Obstetric and Neonatal Nurses; and the American College of Nurse-Midwives have joined the CDC and the March of Dimes in emphasizing the need for immunization for pregnant and postpartum women.

Why should pregnant and postpartum women receive the seasonal influenza vaccine? Consider the following four reasons:

  • Influenza is more likely to cause severe illness in pregnant women than in women who are not pregnant. Changes in the immune system, heart, and lungs during pregnancy make pregnant women more prone to severe illness from the flu.
  • Risk of premature labor and delivery is heightened in pregnant women with influenza.
  • Vaccination during pregnancy has been shown to protect the mother and baby (up to six months old) from lab-confirmed influenza. Influenza hospitalization rates in infants less than six months of age are more than 10 times that of older children.
  • Pregnant women accounted for 5% of 2009 U.S. H1N1 influenza deaths, while only about 1% of the population was pregnant. Severe illness in postpartum women also was documented.2

Vaccine is safe

Educate pregnant and postpartum women about the importance of getting the seasonal flu shot, as well as the safety of the vaccine. Results of a cross-sectional study of 813 postpartum women during the 2009-10 flu season at the Aurora, CO-based University of Colorado Hospital indicate that many women might not be getting the message. Women in the study who chose not to receive the seasonal or H1N1 vaccine cited the following reasons: not knowledgeable about the importance of vaccination (25%), concern for effects on fetal health (18%), concern for effects on maternal health (9%), and not knowing where to obtain vaccination (9%).3

How can clinicians get the message across to patients? Number one: Be sure to get immunized, so you can serve as a good role for patients, says Barbra Fisher, MD, PhD, a maternal fetal medicine fellow/instructor at the University of Colorado, Denver, and lead author of the study. Educate patients about the safety of the vaccination for mother and baby, she advocates.

Emphasize the following points about safety:

  • Influenza vaccines have been given to millions of pregnant women over the last decade and have not been shown to cause harm to women or their infants.
  • The flu shot can be administered to pregnant women in any trimester.
  • Pregnant women should receive inactivated vaccine, which is used in the flu shot, but should not receive the live attenuated vaccine, which is used in the nasal spray.
  • Postpartum women, even if breastfeeding, can receive either type of vaccine.

Also, talk about potential complications for pregnant women who contract influenza, says Fisher. Explain that the best way to avoid those complications is become vaccinated, she states.


  1. American Academy of Family Physicians News Staff. AAFP, other groups stress need for pregnant, postpartum women to be immunized against flu. AAFP News Now, Sept. 15, 2010. Accessed at
  2. Centers for Disease Control and Prevention, March of Dimes, American Academy of Family Physicians, American Medical Association, American Academy of Pediatrics, American College of Obstetricians and Gynecologists, American Pharmacists Association, Association of Women's Health, Obstetric and Neonatal Nurses, American College of Nurse-Midwives. Dear Colleague letter. Accessed at
  3. Fisher B. Behaviors, attitudes, and perceptions regarding seasonal and H1N1 influenza vaccination during the 2009-2010 season. Presented at the 37th Annual Scientific Meeting of the Infectious Diseases Society for Obstetrics and Gynecology. Santa Fe; August 2010.