title: [Effect of submicroscopic or polyclonal Plasmodium falciparum infection on mother and gestation product: systematic review].
abstract: BACKGROUND
  Malaria in pregnancy causes substantial maternal and infant morbidity-mortality, even at submicroscopic parasite levels. In addition, the presence of polyclonal infections secondary to high parasite genetic diversity is a common finding.
  
  
  OBJECTIVE
  To determine the frequency of submicroscopic and/or polyclonal plasmodial infection during pregnancy and to establish their impact on clinical presentation, immunity acquisition, and consequences on mother and gestation product.
  
  
  METHODS
  A search on Medline was performed using key words (MeSH): pregnancy, malaria, PCR, microscopy, genotype, and clones. Studies on plasmodial infection diagnosed by microscopy and PCR were selected.
  
  
  RESULTS
  A total of 16 studies were included, all carried out in Africa. The weighted mean (WM) of submicroscopic infection was 36%. According to type of infection (microscopic, submicroscopic or negative), the WM of maternal anemia and low birth weight (LBW) were 51%, 42%, 33%, and 19%, 16%, 11%, respectively. Risks (OR), using the negative group as reference, were: a) for maternal anemia 2.12 in microscopic infection and 1.48 in submicroscopic; b) for LBW 1.89 in microscopic and 1.56 in submicroscopic infection. The WM of polyclonal infection was 75% and the mean number of clones by sample was three.
  
  
  CONCLUSIONS
  Submicroscopic and polyclonal P. falciparum infections during pregnancy are very common, but have been little studied and their impact must be assessed in each specific region because they depend on malaria transmission intensity and stability, maternal age and parity, among other variables, which are influenced by environmental and socio-economic conditions of each region.
authors.affiliation: Facultad de Medicina, Universidad de Antioquia, Carrera 51D 62-29, oficina 336, Medellín, Colombia. emarango@gmail.com
authors.forename: Eliana
authors.initials: E
authors.lastname: Arango
authors.forename: Amanda
authors.initials: A
authors.lastname: Maestre
authors.forename: Jaime
authors.initials: J
authors.lastname: Carmona-Fonseca
mesh_terms: D005260:Female; D006801:Humans; D007231:Infant, Newborn; D016778:Malaria, Falciparum / Q000175:diagnosis / Q000453:epidemiology; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000175:diagnosis / Q000453:epidemiology; D011256:Pregnancy Outcome