Connect the Dots—February 2018
Obstet Gynecol 2018;131:364–69
Maternal immunization against pertussis is recommended by the Centers for Disease Control and Prevention between 27 and 35 6/7 weeks of gestation. The purpose is primarily to protect the neonate from pertussis during the window between birth and 6 months, when the completion of the infant immunization schedule for pertussis is complete. The gestational age window for administration is almost 10 weeks, which prompts the question of whether systems should be in place to maximize vaccination uptake earlier or later in that window. Does maternal antipertussis antibody available to the fetus wane over that period?
In this prospective cohort study, Abraham et al1 (see page 364) measured maternal and cord antipertussis immunoglobulin G levels for two groups: earlier compared with later maternal immunization between 27 and 35 6/7 weeks. Remarkably, the cord blood levels exceeded those of the mother in both groups and were adequate to provide passive protection to the neonate in both groups as well.
There are two important take-homes from this study for me. Although it is reasonable for a practice to have a system in place to assure that women receive the tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccination, it is not necessary to target a particular gestational age within the recommended window. Second, it is critical to study pharmacokinetics in pregnancy to really understand what happens to drugs in the mother and the fetus. Pregnant women and the fetoplacental unit have very different physiology than other systems, and decisions about treatment in pregnant women should be data-driven—on data derived from pregnant women.
Nancy C. Chescheir, MD
University of North Carolina, Chapel Hill, Chapel Hill, North Carolina
1. Abraham C, Pichichero M, Eisenberg J, Singh S. Third-trimester maternal vaccination against pertussis and pertussis antibody concentrations. Obstet Gynecol 2018;131:364–69.