Initial unsolicited report received from literature on 13-Sep-2017. Abstract: Researchers studying the flu vaccine in pregnancy have found a hint of a possible link between miscarriage early in pregnancy and the flu vaccine in women who received a certain version of the vaccine two years in a row. It's the first study to identify a potential link between miscarriage and the flu vaccine and the first to assess the effect of repeat influenza vaccination and risk of miscarriage. "I think it's really important for women to understand that this is a possible link, and it is a possible link that needs to be studied and needs to be looked at over more [flu] seasons," said senior adviser for vaccines at the Centers for Disease Control and Prevention, which funded the study. The CDC, the College and the study authors continue to recommend that pregnant women get a flu vaccine during any stage of pregnancy because of the danger influenza poses to women and their developing babies. Vaccination during pregnancy is also the most effective strategy to protect newborns, experts say, because the flu vaccine is not approved for use in infants younger than six months. The authors also said the results could be biased if women who sought care for their miscarriages were also more likely to have received flu vaccinations. Miscarriages, which are among the most challenging birth outcomes to study, often occur early in pregnancy and don't necessarily come to the attention of health-care providers or the women themselves if they miscarry before they realize they are pregnant. If women who routinely get flu vaccines are also more likely to be aware of pregnancies earlier than other women or more likely to seek care before or after a miscarriage, that could explain the study findings. This case involves 17 female patient's (reported ages 18-44) who were vaccinated with a dose of INFLUENZA VACCINE (Batch number, expiration date, dose, route and site of administration was not reported) on an unspecified date while they are pregnant. Pregnancy information: LMP, estimated delivery date, pregnancy trimester were not reported. The patient's medical history and concomitant medications were not reported. On an unspecified date, 28 days following the vaccination, the patient's had miscarriage early in pregnancy. It was reported that, most miscarriages occurred in the first trimester, but several occurred during the second trimester. The median age of the fetus at time of miscarriage was 7 weeks. It was also reported that, the patient previously had vaccinated with flu vaccines. It was also a case of vaccine exposure during pregnancy. Lab data and corrective treatment were not reported. Upon internal review, the company decided to consider the event serious because of important medical event miscarriage. List of documents held by sender: none. Sender's Comments: In this case pregnant women received influenza vaccine and had miscarriage. Time to onset is compatible with the role of vaccine. It was reported that the patients were immunized in the prior flu season and most miscarriages occurred in the first trimester but several occurred during the second trimester and that the median age of the fetus at time of miscarriage was 7 weeks. Further information regarding medical history, immune status at the time of vaccination, laboratory investigations excluding alternative etiologies would be needed to fully assess this case. Based upon available information the role of the vaccine could not be assessed.