Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate, Inc. and/or its affiliates. All Rights Reserved.

Influenza and pregnancy

Denise J Jamieson, MD, MPH
Sonja A Rasmussen, MD, MS
Section Editors
Vincenzo Berghella, MD
Martin S Hirsch, MD
Deputy Editor
Vanessa A Barss, MD, FACOG


Pregnant women with influenza are more likely to develop severe illness and to die than the general population, based on data from seasonal influenza and from the influenza pandemics of 1918 to 1919, 1957 to 1958, and 2009 to 2010. The increased severity of influenza in pregnant women is thought to be related to normal physiologic changes that occur during pregnancy. For example, heart rate and oxygen consumption increase, lung capacity decreases, and there is a shift away from cell-mediated immunity.

Because of the increased severity of influenza in pregnancy, inactivated influenza vaccine is recommended for pregnant women, regardless of trimester of pregnancy. In addition, pregnant women with suspected or confirmed influenza should receive prompt empiric treatment with an appropriate antiviral medication.


Clinical manifestations of influenza in pregnant women are similar to those in the general population, and include fever, cough, rhinorrhea, sore throat, headache, shortness of breath, and myalgia [1]. (See "Clinical manifestations of seasonal influenza in adults".)


The diagnosis of influenza should be made clinically, since it is critical to initiate appropriate treatment promptly in pregnant women. (See "Diagnosis of seasonal influenza in adults".)

Diagnostic influenza laboratory tests in pregnant women are the same as those for other high-risk patients. (See "Diagnosis of seasonal influenza in adults".)

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:

Subscribers log in here

Literature review current through: Sep 2017. | This topic last updated: Oct 04, 2017.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.
  1. Jamieson DJ, Honein MA, Rasmussen SA, et al. H1N1 2009 influenza virus infection during pregnancy in the USA. Lancet 2009; 374:451.
  2. Mosby LG, Rasmussen SA, Jamieson DJ. 2009 pandemic influenza A (H1N1) in pregnancy: a systematic review of the literature. Am J Obstet Gynecol 2011; 205:10.
  3. Mertz D, Kim TH, Johnstone J, et al. Populations at risk for severe or complicated influenza illness: systematic review and meta-analysis. BMJ 2013; 347:f5061.
  4. FREEMAN DW, BARNO A. Deaths from Asian influenza associated with pregnancy. Am J Obstet Gynecol 1959; 78:1172.
  5. Hardy JM, Azarowicz EN, Mannini A, et al. The effect of Asian influenza on the outcome of pregnancy, Baltimore, 1957-1958. Am J Public Health Nations Health 1961; 51:1182.
  6. Harris JW. Influenza occurring in pregnant women. JAMA 1919; 72:978.
  7. Nuzum JW, Pilot I, Stangl FH, Bonar BE. 1918 pandemic influenza and pneumonia in a large civil hospital. IMJ Ill Med J 1976; 150:612.
  8. Dodds L, McNeil SA, Fell DB, et al. Impact of influenza exposure on rates of hospital admissions and physician visits because of respiratory illness among pregnant women. CMAJ 2007; 176:463.
  9. Neuzil KM, Reed GW, Mitchel EF, et al. Impact of influenza on acute cardiopulmonary hospitalizations in pregnant women. Am J Epidemiol 1998; 148:1094.
  10. Siston AM, Rasmussen SA, Honein MA, et al. Pandemic 2009 influenza A(H1N1) virus illness among pregnant women in the United States. JAMA 2010; 303:1517.
  11. Callaghan WM, Creanga AA, Jamieson DJ. Pregnancy-Related Mortality Resulting From Influenza in the United States During the 2009-2010 Pandemic. Obstet Gynecol 2015; 126:486.
  12. Meijer WJ, van Noortwijk AG, Bruinse HW, Wensing AM. Influenza virus infection in pregnancy: a review. Acta Obstet Gynecol Scand 2015; 94:797.
  13. Irving WL, James DK, Stephenson T, et al. Influenza virus infection in the second and third trimesters of pregnancy: a clinical and seroepidemiological study. BJOG 2000; 107:1282.
  14. Gu J, Xie Z, Gao Z, et al. H5N1 infection of the respiratory tract and beyond: a molecular pathology study. Lancet 2007; 370:1137.
  15. Luteijn JM, Brown MJ, Dolk H. Influenza and congenital anomalies: a systematic review and meta-analysis. Hum Reprod 2014; 29:809.
  16. Moretti ME, Bar-Oz B, Fried S, Koren G. Maternal hyperthermia and the risk for neural tube defects in offspring: systematic review and meta-analysis. Epidemiology 2005; 16:216.
  17. Centers for Disease Control and Prevention (CDC). Maternal and infant outcomes among severely ill pregnant and postpartum women with 2009 pandemic influenza A (H1N1)--United States, April 2009-August 2010. MMWR Morb Mortal Wkly Rep 2011; 60:1193.
  18. Bloom-Feshbach K, Simonsen L, Viboud C, et al. Natality decline and miscarriages associated with the 1918 influenza pandemic: the Scandinavian and United States experiences. J Infect Dis 2011; 204:1157.
  19. McNeil SA, Dodds LA, Fell DB, et al. Effect of respiratory hospitalization during pregnancy on infant outcomes. Am J Obstet Gynecol 2011; 204:S54.
  20. Mendez-Figueroa H, Raker C, Anderson BL. Neonatal characteristics and outcomes of pregnancies complicated by influenza infection during the 2009 pandemic. Am J Obstet Gynecol 2011; 204:S58.
  21. Yates L, Pierce M, Stephens S, et al. Influenza A/H1N1v in pregnancy: an investigation of the characteristics and management of affected women and the relationship to pregnancy outcomes for mother and infant. Health Technol Assess 2010; 14:109.
  22. Håberg SE, Trogstad L, Gunnes N, et al. Risk of fetal death after pandemic influenza virus infection or vaccination. N Engl J Med 2013; 368:333.
  23. Grohskopf LA, Sokolow LZ, Broder KR, et al. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices - United States, 2017-18 Influenza Season. MMWR Recomm Rep 2017; 66:1.
  24. Centers for Disease Control and Prevention (CDC). Influenza vaccination coverage among pregnant women--United States, 2012-13 influenza season. MMWR Morb Mortal Wkly Rep 2013; 62:787.
  25. Committee on Obstetric Practice and Immunization Expert Work Group, Centers for Disease Control and Prevention’s Advisory Committee on Immunization, United States, American College of Obstetricians and Gynecologists. Committee opinion no. 608: influenza vaccination during pregnancy. Obstet Gynecol 2014; 124:648.
  26. Ding H, Black CL, Ball S, et al. Influenza Vaccination Coverage Among Pregnant Women - United States, 2016-17 Influenza Season. MMWR Morb Mortal Wkly Rep 2017; 66:1016.
  27. http://immunizationforwomen.org/downloads/Toolkits/Flu/Flu-vaccine-Physicians-Script-2013.pdf (Accessed on April 05, 2016).
  28. Madhi SA, Cutland CL, Kuwanda L, et al. Influenza vaccination of pregnant women and protection of their infants. N Engl J Med 2014; 371:918.
  29. Jamieson DJ, Kissin DM, Bridges CB, Rasmussen SA. Benefits of influenza vaccination during pregnancy for pregnant women. Am J Obstet Gynecol 2012; 207:S17.
  30. Schlaudecker EP, McNeal MM, Dodd CN, et al. Pregnancy modifies the antibody response to trivalent influenza immunization. J Infect Dis 2012; 206:1670.
  31. Demicheli V, Jefferson T, Al-Ansary LA, et al. Vaccines for preventing influenza in healthy adults. Cochrane Database Syst Rev 2014; :CD001269.
  32. Zaman K, Roy E, Arifeen SE, et al. Effectiveness of maternal influenza immunization in mothers and infants. N Engl J Med 2008; 359:1555.
  33. Thompson MG, Li DK, Shifflett P, et al. Effectiveness of seasonal trivalent influenza vaccine for preventing influenza virus illness among pregnant women: a population-based case-control study during the 2010-2011 and 2011-2012 influenza seasons. Clin Infect Dis 2014; 58:449.
  34. Bratton KN, Wardle MT, Orenstein WA, Omer SB. Maternal influenza immunization and birth outcomes of stillbirth and spontaneous abortion: a systematic review and meta-analysis. Clin Infect Dis 2015; 60:e11.
  35. Steinhoff MC, Omer SB, Roy E, et al. Neonatal outcomes after influenza immunization during pregnancy: a randomized controlled trial. CMAJ 2012; 184:645.
  36. Omer SB, Goodman D, Steinhoff MC, et al. Maternal influenza immunization and reduced likelihood of prematurity and small for gestational age births: a retrospective cohort study. PLoS Med 2011; 8:e1000441.
  37. Fell DB, Sprague AE, Liu N, et al. H1N1 influenza vaccination during pregnancy and fetal and neonatal outcomes. Am J Public Health 2012; 102:e33.
  38. Legge A, Dodds L, MacDonald NE, et al. Rates and determinants of seasonal influenza vaccination in pregnancy and association with neonatal outcomes. CMAJ 2014; 186:E157.
  39. Olsen SJ, Frank-Stromborg M. Cancer prevention and screening activities reported by African-American nurses. Oncol Nurs Forum 1994; 21:487.
  40. Eick AA, Uyeki TM, Klimov A, et al. Maternal influenza vaccination and effect on influenza virus infection in young infants. Arch Pediatr Adolesc Med 2011; 165:104.
  41. Poehling KA, Szilagyi PG, Staat MA, et al. Impact of maternal immunization on influenza hospitalizations in infants. Am J Obstet Gynecol 2011; 204:S141.
  42. Benowitz I, Esposito DB, Gracey KD, et al. Influenza vaccine given to pregnant women reduces hospitalization due to influenza in their infants. Clin Infect Dis 2010; 51:1355.
  43. Shakib JH, Korgenski K, Presson AP, et al. Influenza in Infants Born to Women Vaccinated During Pregnancy. Pediatrics 2016; 137.
  44. Nunes MC, Cutland CL, Jones S, et al. Duration of Infant Protection Against Influenza Illness Conferred by Maternal Immunization: Secondary Analysis of a Randomized Clinical Trial. JAMA Pediatr 2016; 170:840.
  45. Tapia MD, Sow SO, Tamboura B, et al. Maternal immunisation with trivalent inactivated influenza vaccine for prevention of influenza in infants in Mali: a prospective, active-controlled, observer-blind, randomised phase 4 trial. Lancet Infect Dis 2016; 16:1026.
  46. Wutzler P, Schmidt-Ott R, Hoyer H, Sauerbrei A. Prevalence of influenza A and B antibodies in pregnant women and their offspring. J Clin Virol 2009; 46:161.
  47. Schlaudecker EP, Steinhoff MC, Omer SB, et al. IgA and neutralizing antibodies to influenza a virus in human milk: a randomized trial of antenatal influenza immunization. PLoS One 2013; 8:e70867.
  48. Groothuis JR, Levin MJ, Rabalais GP, et al. Immunization of high-risk infants younger than 18 months of age with split-product influenza vaccine. Pediatrics 1991; 87:823.
  49. Halasa NB, Gerber MA, Chen Q, et al. Safety and immunogenicity of trivalent inactivated influenza vaccine in infants. J Infect Dis 2008; 197:1448.
  50. Nunes MC, Cutland CL, Jones S, et al. Efficacy of maternal influenza vaccination against all-cause lower respiratory tract infection hospitalizations in young infants: Results from a randomized controlled trial. Clin Infect Dis 2017.
  51. Regan AK, de Klerk N, Moore HC, et al. Effect of Maternal Influenza Vaccination on Hospitalization for Respiratory Infections in Newborns: A Retrospective Cohort Study. Pediatr Infect Dis J 2016; 35:1097.
  52. De Wals P, Deceuninck G, Toth E, et al. Risk of Guillain-Barré syndrome following H1N1 influenza vaccination in Quebec. JAMA 2012; 308:175.
  53. Tamma PD, Ault KA, del Rio C, et al. Safety of influenza vaccination during pregnancy. Am J Obstet Gynecol 2009; 201:547.
  54. Pasternak B, Svanström H, Mølgaard-Nielsen D, et al. Risk of adverse fetal outcomes following administration of a pandemic influenza A(H1N1) vaccine during pregnancy. JAMA 2012; 308:165.
  55. Irving SA, Kieke BA, Donahue JG, et al. Trivalent inactivated influenza vaccine and spontaneous abortion. Obstet Gynecol 2013; 121:159.
  56. Nordin JD, Kharbanda EO, Benitez GV, et al. Maternal safety of trivalent inactivated influenza vaccine in pregnant women. Obstet Gynecol 2013; 121:519.
  57. Kharbanda EO, Vazquez-Benitez G, Lipkind H, et al. Inactivated influenza vaccine during pregnancy and risks for adverse obstetric events. Obstet Gynecol 2013; 122:659.
  58. Nordin JD, Kharbanda EO, Vazquez Benitez G, et al. Maternal influenza vaccine and risks for preterm or small for gestational age birth. J Pediatr 2014; 164:1051.
  59. Fell DB, Platt RW, Lanes A, et al. Fetal death and preterm birth associated with maternal influenza vaccination: systematic review. BJOG 2015; 122:17.
  60. Polyzos KA, Konstantelias AA, Pitsa CE, Falagas ME. Maternal Influenza Vaccination and Risk for Congenital Malformations: A Systematic Review and Meta-analysis. Obstet Gynecol 2015; 126:1075.
  61. Regan AK, Moore HC, de Klerk N, et al. Seasonal Trivalent Influenza Vaccination During Pregnancy and the Incidence of Stillbirth: Population-Based Retrospective Cohort Study. Clin Infect Dis 2016; 62:1221.
  62. Ludvigsson JF, Ström P, Lundholm C, et al. Risk for Congenital Malformation With H1N1 Influenza Vaccine: A Cohort Study With Sibling Analysis. Ann Intern Med 2016; 165:848.
  63. Zerbo O, Qian Y, Yoshida C, et al. Association Between Influenza Infection and Vaccination During Pregnancy and Risk of Autism Spectrum Disorder. JAMA Pediatr 2017; 171:e163609.
  64. Hviid A, Svanström H, Mølgaard-Nielsen D, Lambach P. Association Between Pandemic Influenza A(H1N1) Vaccination in Pregnancy and Early Childhood Morbidity in Offspring. JAMA Pediatr 2017; 171:239.
  65. Donahue JG, Kieke BA, King JP, et al. Association of spontaneous abortion with receipt of inactivated influenza vaccine containing H1N1pdm09 in 2010-11 and 2011-12. Vaccine 2017; 35:5314.
  66. Jamieson DJ, Rasmussen SA. The safety of adjuvants in influenza vaccines during pregnancy: what do we know and why do we need them? Am J Obstet Gynecol 2012; 207:145.
  67. Heikkinen T, Young J, van Beek E, et al. Safety of MF59-adjuvanted A/H1N1 influenza vaccine in pregnancy: a comparative cohort study. Am J Obstet Gynecol 2012; 207:177.e1.
  68. Källén B, Olausson PO. Vaccination against H1N1 influenza with Pandemrix(®) during pregnancy and delivery outcome: a Swedish register study. BJOG 2012; 119:1583.
  69. Rasmussen SA, Kissin DM, Yeung LF, et al. Preparing for influenza after 2009 H1N1: special considerations for pregnant women and newborns. Am J Obstet Gynecol 2011; 204:S13.
  70. Fiore AE, Fry A, Shay D, et al. Antiviral agents for the treatment and chemoprophylaxis of influenza --- recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 2011; 60:1.
  71. Prevention strategies for seasonal influenza in healthcare settings. http://www.cdc.gov/flu/professionals/infectioncontrol/healthcaresettings.htm (Accessed on October 03, 2012).
  72. http://www.cdc.gov/flu/professionals/infectioncontrol/healthcaresettings.htm (Accessed on December 01, 2015).
  73. Walter EB, Allred NJ, Swamy GK, et al. Influenza vaccination of household contacts of newborns: a hospital-based strategy to increase vaccination rates. Infect Control Hosp Epidemiol 2010; 31:1070.
  74. Wentges-van Holthe N, van Eijkeren M, van der Laan JW. Oseltamivir and breastfeeding. Int J Infect Dis 2008; 12:451.
  75. Greer LG, Leff RD, Rogers VL, et al. Pharmacokinetics of oseltamivir according to trimester of pregnancy. Am J Obstet Gynecol 2011; 204:S89.
  76. Oseltamivir http://toxnet.nlm.nih.gov/newtoxnet/lactmed.htm (Accessed on December 14, 2015).
  77. Louie JK, Wadford DA, Norman A, Jamieson DJ. 2009 pandemic influenza A (H1N1) and vaccine failure in pregnancy. Obstet Gynecol 2011; 117:470.
  78. http://www.cdc.gov/flu/professionals/antivirals/avrec_ob2011.htm (Accessed on October 03, 2012).
  79. Louie JK, Jamieson DJ, Rasmussen SA. 2009 pandemic influenza A (H1N1) virus infection in postpartum women in California. Am J Obstet Gynecol 2011; 204:144.e1.
  80. Louie JK, Acosta M, Jamieson DJ, et al. Severe 2009 H1N1 influenza in pregnant and postpartum women in California. N Engl J Med 2010; 362:27.
  81. Creanga AA, Johnson TF, Graitcer SB, et al. Severity of 2009 pandemic influenza A (H1N1) virus infection in pregnant women. Obstet Gynecol 2010; 115:717.
  82. Hansen C, Desai S, Bredfeldt C, et al. A large, population-based study of 2009 pandemic Influenza A virus subtype H1N1 infection diagnosis during pregnancy and outcomes for mothers and neonates. J Infect Dis 2012; 206:1260.
  83. Muthuri SG, Venkatesan S, Myles PR, et al. Effectiveness of neuraminidase inhibitors in reducing mortality in patients admitted to hospital with influenza A H1N1pdm09 virus infection: a meta-analysis of individual participant data. Lancet Respir Med 2014; 2:395.
  84. Oboho IK, Reed C, Gargiullo P, et al. Benefit of Early Initiation of Influenza Antiviral Treatment to Pregnant Women Hospitalized With Laboratory-Confirmed Influenza. J Infect Dis 2016; 214:507.
  85. Rasmussen SA, Jamieson DJ, Macfarlane K, et al. Pandemic influenza and pregnant women: summary of a meeting of experts. Am J Public Health 2009; 99 Suppl 2:S248.
  86. Greer LG, Sheffield JS, Rogers VL, et al. Maternal and neonatal outcomes after antepartum treatment of influenza with antiviral medications. Obstet Gynecol 2010; 115:711.
  87. Tanaka T, Nakajima K, Murashima A, et al. Safety of neuraminidase inhibitors against novel influenza A (H1N1) in pregnant and breastfeeding women. CMAJ 2009; 181:55.
  88. Xie HY, Yasseen AS 3rd, Xie RH, et al. Infant outcomes among pregnant women who used oseltamivir for treatment of influenza during the H1N1 epidemic. Am J Obstet Gynecol 2013; 208:293.e1.
  89. Saito S, Minakami H, Nakai A, et al. Outcomes of infants exposed to oseltamivir or zanamivir in utero during pandemic (H1N1) 2009. Am J Obstet Gynecol 2013; 209:130.e1.
  90. http://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm (Accessed on April 05, 2016).
  91. Fiore AE, Fry A, Shay D, et al. Antiviral agents for the treatment and chemoprophylaxis of influenza --- recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 2011; 60:1.
  92. Edwards MJ. Review: Hyperthermia and fever during pregnancy. Birth Defects Res A Clin Mol Teratol 2006; 76:507.
  93. Petrova A, Demissie K, Rhoads GG, et al. Association of maternal fever during labor with neonatal and infant morbidity and mortality. Obstet Gynecol 2001; 98:20.