Initial unsolicited literature report received from a physician on 16 June 2015. This case is linked to 2015SA092506, 2015SA092507, 2015SA092508, 2015SA092509, 2015SA092510, 2015SA092511, 2015SA089479, 2015SA092722, 2015SA092723, 2015SA092724, 2015SA092725 (same vaccine). Abstracts: OBJECTIVE: To evaluate pregnancy outcomes of women who received Tdap vaccination at or after 32 weeks of gestation. Outcomes from consecutive pregnancies during which the mother received Tdap were also analyzed. METHODS: In a retrospective cohort study at a single institution, we compared pregnancy outcomes between those who accepted or declined Tdap at 32 weeks of gestation. Additionally, women who received Tdap vaccination in this and a prior pregnancy in the past 5 years were compared with multiparous women who only received Tdap in this pregnancy. RESULTS: Since 2013, 7,378 women who were offered the Tdap vaccine antenatally delivered at our institution: 7,152 accepted (97 percentage). There was no difference in stillbirths, major malformations, chorioamnionitis, 5-minute Apgar score, or cord blood pH. Neonatal complications including ventilation requirement, sepsis, intraventricular hemorrhage, and neonatal death were also similar. However, preterm birth rates at 36 weeks of gestation or less (6 percentage compared with 12 percentage, P less than 001), incidence of small for gestational age (10 percentage compared with 15 percentage, P equal to 03), and length of neonatal hospitalization (3.9 compared with 4.7 days, P, .001) were all significantly increased in the unvaccinated cohort. No difference in neonatal outcomes was noted between women who were administered at least two Tdap vaccines in the past 5 years (n equal to 1,229) and those who received only a single dose (n equal to 4,159). CONCLUSION: No adverse pregnancy outcomes were identified in association with antepartum Tdap vaccination. This remained true in women receiving more than one Tdap vaccine in a 5-year timeframe. This may be the result of a type II error. A 7,378 number of female patients out of which 7,152 (97 percentage) patients received Tdap vaccine and 226 (3 percentage) patients declined Tdap vaccine. A 7,152 number of female patients, whose medical history and concomitant medication were not reported had received a dose of Tdap (batch number, expiration date, dose, dose number, route and site of administration were not reported) on an unspecified date. A 7,152 number of patients out of which 421 (6 percentage) numbers of patients experienced chorioamnionitis on an unspecified date. It was reported that, a small but statistically significant increase in chorioamnionitis was reported in vaccinated women. This is in contrast to study, which found no increase in chorioamnionitis rates among immunized women. Findings further support that Tdap vaccine receipt during pregnancy is not associated with an increased risk of adverse pregnancy outcomes and also provides initial outcome information on women receiving multiple doses of vaccine in a short timespan. Laboratory investigation and corrective treatment were not reported. The last menstrual period was not reported. The patient was pregnant at the time of vaccination, thus it was vaccine exposure during pregnancy. At the time of this report, the outcome of the event was unknown. Upon internal review, company assessed the event of chorioamnionitis and vaccine exposure during pregnancy as serious and medically significant. Documents held by sender: none.