Abraham C, et al. - The authors aimed to perform a comparison of pertussis antibody concentrations in maternal venous serum (at the time of delivery) and umbilical cord arterial serum among women vaccinated with the tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine from either 27–30 6/7 weeks of gestation or from 31–35 6/7 weeks of gestation. Between 27 and 36 weeks of gestation, maternal vaccination against pertussis was associated with a high percentage of newborns with antibody concentrations conferring protection. This did not vary by gestational age at vaccination.