BACKGROUND: Passively acquired respiratory syncytial virus (RSV)-neutralizing antibody protects against RSV-associated lower respiratory infections but placental malaria (PM) and maternal hypergammaglobulinemia might interfere with transplacental immunoglobulin transport. METHODS: We measured RSV plaque reduction neutralization (PRN) antibody titers in 300 full-term maternal/cord serum pairs in two cohorts in malaria-endemic Papua New Guinea: Alexishafen (2005-08) and FIS (2011-13). We defined impaired transport as a cord to maternal titer ratio (CMTR) <1.0 and a protective RSV PRN titer (PRNT) as >/=1:200. RESULTS: PM and hypergammaglobulinemia occurred in 60% and 54% of Alexishafen mothers versus 8% and 9% of FIS mothers, respectively. 34% of Alexishafen and 32% of FIS pairs demonstrated impaired transport. Multivariate modeling revealed significant associations between increasing maternal IgG (log2) and impaired transport (adjusted OR, Alexishafen: 2.68 [1.17-6.14], FIS: 6.94; [1.94-24.8]) but no association with PM. 34% of Alexishafen and 31% of FIS cord PRNTs were <1:200. CONCLUSIONS: Impaired RSV Ab transport was observed in approximately one-third of maternal/cord pairs. Hypergammaglobulinemia, but not PM, was associated with impaired transport, particularly among women with low RSV PRNT. Detection of RSV PRNT <1:200 in one-third of cord sera supports efforts to increase levels of RSV neutralizing antibody in pregnant women through maternal immunization.