title: Prevalence of early-onset neonatal infection among newborns of mothers with bacterial infection or colonization: a systematic review and meta-analysis.
abstract: BACKGROUND
  Although neonatal infections cause a significant proportion of deaths in the first week of life, little is known about the burden of neonatal disease originating from maternal infection or colonization globally. This paper describes the prevalence of vertical transmission--the percentage of newborns with neonatal infection among newborns exposed to maternal infection.
  
  
  METHODS
  We searched Pubmed, Embase, Scopus, Web of Science, Cochrane Library, and WHO Regional Databases for studies of maternal infection, vertical transmission, and neonatal infection. Studies that measured prevalence of bacterial vertical transmission were included. Random effects meta-analyses were used to pool data to calculate prevalence estimates of vertical transmission.
  
  
  RESULTS
  122 studies met the inclusion criteria. Only seven studies (5.7%) were from very high neonatal mortality settings. Considerable heterogeneity existed between studies given the various definitions of infection (lab-confirmed, clinical signs), colonization, and risk factors of infection. The prevalence of early onset neonatal lab-confirmed infection among newborns of mothers with lab-confirmed infection was 17.2% (95%CI 6.5-27.9). The prevalence of neonatal lab-confirmed infection among newborns of colonized mothers was 0% (95% CI 0.0-0.0). The prevalence of neonatal surface colonization among newborns of colonized mothers ranged from 30.9-45.5% depending on the organism. The prevalence of neonatal lab-confirmed infection among newborns of mothers with risk factors (premature rupture of membranes, preterm premature rupture of membranes, prolonged rupture of membranes) ranged from 2.9-19.2% depending on the risk factor.
  
  
  CONCLUSIONS
  The prevalence of early-onset neonatal infection is high among newborns of mothers with infection or risk factors for infection. More high quality studies are needed particularly in high neonatal mortality settings to accurately estimate the prevalence of early-onset infection among newborns at risk.
authors.affiliation: Boston Children's Hospital, Boston, MA, 02115, USA. grace.chan@childrens.harvard.edu.|Harvard T.H. Chan School of Public Health, Boston, MA, USA. grace.chan@childrens.harvard.edu.
authors.forename: Grace J
authors.initials: GJ
authors.lastname: Chan
authors.affiliation: Brigham and Women's Hospital, Boston, MA, USA. alee6@partners.org.
authors.forename: Anne C C
authors.initials: AC
authors.lastname: Lee
authors.affiliation: Johns Hopkins School of Public Health, Baltimore, MD, 21205, USA. abaqui@jhsph.edu.
authors.forename: Abdullah H
authors.initials: AH
authors.lastname: Baqui
authors.affiliation: Johns Hopkins School of Public Health, Baltimore, MD, 21205, USA. jitan@jhsph.edu.
authors.forename: Jingwen
authors.initials: J
authors.lastname: Tan
authors.affiliation: Johns Hopkins School of Public Health, Baltimore, MD, 21205, USA. rblack@jhsph.edu.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Black
mesh_terms: D001424:Bacterial Infections / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D005260:Female; D014943:Global Health; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000453:epidemiology / Q000517:prevention & control; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control*; D009035:Mothers; D015995:Prevalence; D012307:Risk Factors