chorioamnionitis; patients were pregnant at the time of vaccination with TDaP; 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).   This case involves 421 pregnant female patients of unknown age who experienced chorioamnionitis (amniotic cavity infection), while receiving DIPHTHERIA, TETANUS AND ACELLULAR PERTUSSIS VACCINE (Exposure during pregnancy).  Data regarding this pregnancy were received prospectively.   The date of last menstrual period was not reported. Gestation period was not reported  The estimated due date was not reported.  The actual date of delivery was not reported.  Medical history, medical treatment, vaccination, concomitant medication and family history were not provided.  On an unknown date, the patients received a dose of suspect DIPHTHERIA, TETANUS AND ACELLULAR PERTUSSIS VACCINE produced by unknown manufacturer (lot number and expiry date: not reported) via an unknown route at an unknown administration site for prophylactic vaccination.  On an unknown date, the patients developed a serious chorioamnionitis (amniotic cavity infection), (unknown latency) following the administration of DIPHTHERIA and TETANUS AND ACELLULAR PERTUSSIS VACCINE. This event was assessed as medically significant.  It was also the case of vaccine exposure during pregnancy (latency-same day).  It was reported that, a small but statistically significant increase in chorioamnionitis was reported in vaccinated women. This was 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 time span.   Details of laboratory data not reported.   It was not reported if the patients received a corrective treatment.  Pregnancy outcome was unknown at the time of report.  At the time of reporting, the outcome of the amniotic cavity infection event was unknown.  There will be no information available on batch number for this case.  Follow-up information received on 19-Apr-2021 regarding an unsolicited non literature valid serious case received from a physician via Regulatory Health Authority (under the reference number: 584306).  The event vaccine exposure during pregnancy made as a diagnosis and remove the seriousness criteria.   Report type and Collection Organization was updated and accordingly narrative was updated.; Sender's Comments: Follow-up information was received on 19-Apr-2021 changes the previous assessment of the case: This case involves 421 pregnant female patients who had amniotic cavity infection, after receiving DIPHTHERIA, TETANUS AND ACELLULAR PERTUSSIS VACCINE (unknown manufacturer). The time to onset is unknown. Additional information regarding patient's medical history, condition at the time of vaccination, lab data excluding other predisposing etiologies would be needed for complete assessment of the case. Based upon the reported information, the role of the vaccine cannot be assessed. US-SA-2015SA089479:CLUSTER US-SA-2015SA092506:CLUSTER US-SA-2015SA092507:CLUSTER US-SA-2015SA092508:CLUSTER US-SA-2015SA092509:CLUSTER US-SA-2015SA092510:CLUSTER US-SA-2015SA092511:CLUSTER US-SA-2015SA092722:CLUSTER US-SA-2015SA092723:CLUSTER US-SA-2015SA092724:CLUSTER US-SA-2015SA092725:CLUSTER