Outcomes of infants born to women with influenza A(H1N1)pdm09

Kim Newsome
C. J. Alverson
Jennifer Williams
Anne F. McIntyre
Anne D. Fine
Cathy Wasserman
Kathryn H. Lofy
Meileen Acosta
Janice K. Louie
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First published: 09 January 2019


Present address Meileen Acosta, Solano County Department of Health and Social Services, 275 Beck Ave, MS 5‐240, Fairfield, CA 94533. and Janice K. Louie, San Francisco Department of Public Health, Zuckerberg San Francisco General Hospital, 1001 Potrero Avenue, Ward 94 San Francisco, CA 94110. and Valoree Stanfield, Intermountain Healthcare, Central Office, 36 South State Street, 17th floor Salt Lake City, UT 84111. and Sonja A. Rasmussen, Departments of Pediatrics and Epidemiology, University of Florida College of Medicine and College of Public Health and Health Professions, 1600 SW Archer Road, PO Box 100296 Gainesville, FL 32610.

Abstract

Background

Pregnant women with influenza are more likely to have complications, but information on infant outcomes is limited.

Methods

Five state/local health departments collected data on outcomes of infants born to pregnant women with 2009 H1N1 influenza reported to the Centers for Disease Control and Prevention from April to December 2009. Collaborating sites linked information on pregnant women with confirmed 2009 H1N1 influenza, many who were severely ill, to their infants' birth certificates. Collaborators also collected birth certificate data from two comparison groups that were matched with H1N1‐affected pregnancies on month of conception, sex, and county of residence.

Results

490 pregnant women with influenza, 1,451 women without reported influenza with pregnancies in the same year, and 1,446 pregnant women without reported influenza with prior year pregnancies were included. Women with 2009 H1N1 influenza admitted to an intensive care unit (ICU; n = 64) were more likely to deliver preterm infants (<37 weeks), low birth weight infants, and infants with Apgar scores <=6 at 5 min than women in comparison groups (adjusted relative risk, aRR = 3.9 [2.7, 5.6], aRR = 4.6 [2.9, 7.5], and aRR = 8.7 [3.6, 21.2], for same year comparisons, respectively). Women with influenza who were not hospitalized and hospitalized women not admitted to the ICU did not have significantly elevated risks for adverse infant outcomes.

Conclusions

Severely ill women with 2009 H1N1 influenza during pregnancy were more likely to have adverse birth outcomes than women without influenza, providing more support for influenza vaccination during pregnancy.