536. Receipt of Trivalent Inactivated Influenza Vaccine is Not Associated with Early Pregnancy Loss
Session: Poster Abstract Session: Influenza Vaccines
Friday, October 21, 2011
Room: Poster Hall B1
  • TIV_IDSA_092711_FINAL.pdf (148.4 kB)
  • Background: 

    The safety of influenza vaccine administered during early pregnancy has been inadequately studied. Administration during the first trimester of pregnancy was not recommended until 2004. Between 1997 and 2004, first trimester influenza vaccination was not encouraged to avoid “coincidental association with spontaneous abortion”. We performed a retrospective case-control study within the Vaccine Safety Datalink (VSD) to examine the association between early pregnancy loss (EPL) at <20 weeks gestation and receipt of influenza vaccine during the prior four weeks.


    Potential cases were identified among women aged 18-44 years who were pregnant during the fall of 2005 or 2006, using electronic ICD-9 codes. Cases of pregnancy loss occurring before 20 weeks gestation were confirmed by medical record review; date of fetal demise was obtained from ultrasound when available. Controls with a live birth or stillbirth beyond 20 weeks were individually matched (1:1) to cases by VSD site and date of last menstrual period. The exposure of interest in the primary analysis was influenza vaccination in the 28 days before the date of EPL (fetal demise) of the matched pair. Conditional logistic regression models adjusted for healthcare utilization, maternal age, and parity.


    Data from 243 matched pairs were analyzed. Eight-two percent of cases had at least one ultrasound performed; mean gestational age at demise was 7.9 weeks. The mean ages of cases and controls were 32 and 29 years, respectively. Older age was strongly associated with EPL (p<0.0001); 66% of cases were ≥30 years of age, compared to 48% of controls. Thirty-eight (16%) cases and 31 (13%) controls received influenza vaccine prior to the matched date of EPL; 16 (7%) cases and 15 (6%) controls were vaccinated within the 28 day risk window before the fetal demise of the matched pair. There was no association between EPL and influenza vaccination in the primary analysis (adjusted odds ratio 1.2, 95% confidence interval [CI] 0.5-2.7, p=0.66).


    We found no association between influenza vaccination and pregnancy loss during the first 20 weeks of gestation.

    Subject Category: I. Adult and Pediatric Vaccines

    Stephanie Irving, MHS1, Burney Kieke, MS1, James Donahue, DVM, PhD1, Maria Mascola, MD2, James Baggs, PhD3, Eric Weintraub, MPH3, Craig Cheetham, PharmD4, Jason Glanz, PhD5, Lisa A. Jackson, MD, MPH6, Allison Naleway, PhD7, James Nordin, MD, MPH8 and Edward Belongia, MD1, (1)Epidemiology Research Center, Marshfield Clinic Research Foundation, Marshfield, WI, (2)Marshfield Clinic, Marshfield , WI, (3)Immunization Safety Office, Centers for Disease Control and Prevention, Atlanta, GA, (4)Kaiser Permanente Southern California, Pasadena, CA, (5)Kaiser Permanente Colorado, Denver, CO, (6)Group Health Cooperative, Seattle, WA, (7)Kaiser Permanente- Northwest, Portland, OR, (8)HealthPartners Research Foundation, Minneapolis, MN


    S. Irving, None

    B. Kieke, None

    J. Donahue, None

    M. Mascola, None

    J. Baggs, None

    E. Weintraub, None

    C. Cheetham, None

    J. Glanz, None

    L. A. Jackson, None

    A. Naleway, None

    J. Nordin, None

    E. Belongia, None

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