This retrospective pregnancy case was reported in a literature article and described the occurrence of pertussis in a infant. The mother received dTpa vaccine. The infant was exposed to dTpa vaccine during the first trimester of pregnancy. On an unknown gestation weeks, the infant was born via unknown delivery method. The mother's last menstrual period was unknown and estimated date of delivery was unknown. The subject's mother received dTpa vaccine during the first trimester of pregnancy. The pregnancy resulted in a live neonate with no apparent congenital anomaly. Less than a year after the mother's vaccination with dTpa vaccine, the infant was diagnosed with pertussis. Serious criteria included GSK medically significant. Additional event(s) included acute respiratory tract infection (serious criteria GSK medically significant), fetal exposure during pregnancy, first trimester and contraindicated drug administered. The outcome of pertussis was unknown. The outcome(s) of the additional event(s) included acute respiratory tract infection (unknown), fetal exposure during pregnancy, first trimester (unknown) and contraindicated drug administered (unknown). The investigator considered that there was a reasonable possibility that the pertussis and acute respiratory tract infection may have been caused by dTpa vaccine. Additional information was provided. This retrospective pregnancy case was reported in a literature article and described the occurrence of pertussis infection in an infant aged less than or equal to 2 months of unspecified gender whose mother was vaccinated with unspecified Tdap vaccine (manufacturer unknown) during first trimester of her pregnancy. The patient was part of the retrospective cohort study that assessed the association between timing of maternal Tdap vaccination during pregnancy and acute respiratory infection (ARI) in infants less than 2 months of age. The study involved 99,434 infants born to women in the Infant Health Registry from 2006 through 2013. The study population was further limited to records with last menstrual period (LMP) and delivery dates between 01 January 2006, and 31 December 2013. [In this study, out of 944 infants (mothers vaccinated between 0 and 13 weeks of pregnancy), 422 were males and 522 were females]. No information on patient's medical history or concurrent condition or concomitant medication was provided. On an unspecified date, the patient's mother had received unspecified Tdap vaccine (administration site and route; dosages unknown; batch number not provided) in the first trimester (between 0 and 13 weeks). (However, it was reported, starting in 2012, the Committee recommended women receive the Tdap vaccination between 27-36 weeks of pregnancy for every pregnancy, regardless of whether they were vaccinated before becoming pregnant, to provide transplacental passive immunity to the infant). (In this study, Tdap vaccination during pregnancy was the exposure of interest; it was defined as the receipt of Tdap vaccine between LMP and delivery date). Subsequently, the patient was exposed to the vaccine in utero. The patient was born on unspecified date. On an unspecified date, in the first 2 months of life, the patient developed acute respiratory infection (ARI). Subsequently, the patient was diagnosed with pertussis infection. Treatment was unknown. The outcome of the event was not reported. The authors did not comment on the relationship between pertussis and unspecified Tdap vaccine. However, the authors commented, it was potentially too early to benefit from transplacental passive immunity. The authors concluded, "Our findings support the current Committee guidelines on Tdap vaccination during pregnancy, which, unfortunately have been slow to be implemented and may require additional intervention. Follow-up studies with more recent years of data and higher rates of compliance may provide more insight into the protective effect of Tdap vaccination over time."