Protection of high-risk infants via maternal antibody: the impact of fetal growth restriction
Alisa Kachikis, MD
BACKGROUND: Maternal immunization, or the vaccination of pregnant women to boost antibody transfer across the placenta to the fetus, is increasingly considered as a disease prevention strategy to protect neonates and infants from pathogens including influenza and respiratory syncytial virus (RSV). Conditions that place neonates at increased risk for respiratory infections and emergent respiratory disease in childhood include placental insufficiency leading to fetal growth restriction (FGR), defined as infants with estimated fetal weight less than the tenth percentile via ultrasound and small for gestational age (SGA) infants with birthweight less than the tenth percentile for gestational age. GAP: The impact of maternal immunization and the efficacy transplacental antibody transfer in pregnancies with abnormal placentas demonstrated by placental insufficiency and leading to FGR and SGA infants is incompletely understood. HYPOTHESIS: We hypothesize that infants from pregnancies with placental insufficiency manifested by FGR and SGA will have decreased transplacental total IgG and influenza-specific IgG transfer compared to term or preterm infants in pregnancies without FGR or SGA, when controlling for gestational age. METHODS: We propose a nested cohort study to examine transplacental antibody transfer by comparing maternal and cord serum pairs total IgG and influenza-specific IgG ratios from FGR and SGA, preterm and term pregnancies. Participants with FGR and SGA and preterm or term pregnancies without FGR or SGA that provide both maternal and umbilical cord samples will be selected from an ongoing prospective parent cohort study at the University of Washington (UW) Medical Center. RESULTS: Pending IMPACT: Given the high prevalence of SGA infants globally along with the growing potential for new maternal vaccines against Group B streptococcus and RSV, this study offers immense opportunity to provide strategies for immune protection against respiratory viruses for infants from pregnancies complicated by FGR and SGA and to inform optimization of vaccine delivery in high- and low-risk pregnancies in order to diminish neonatal infectious morbidity world-wide.