title: A meta-analysis of socio-demographic factors for perinatal mortality in developing countries: a subgroup analysis of the national surveys and small scale studies.
abstract: BACKGROUND
  Although the perinatal mortality in low income countries is about five-folds higher than in the high income countries, little is known about the association of socio-demographic factors with perinatal mortality. National and small scale studies so far reported have shown very contradictory results. The objective of this meta-analysis was to assess the association of perinatal mortality with selected sociodemographic factors.
  
  
  METHODS
  A computer based literature search was conducted mainly in the databases of African Journals Online, MEASURE Demographic and Health Survey (DHS), Google Scholar, HINARI, PUBMED, MEDLINE and the Cochrane Library. The inclusion criteria were: 1) studies that assessed the perinatal mortality in developing countries in relation to socio-demographic predictors and 2) studies published in English and conducted after the year 1990. Subgroup meta-analyses of perinatal mortality were performed for mothers' age, residence, educational level and wealth status. Sensitivity analysis and heterogeneity testing were done.
  
  
  RESULTS
  In this meta-analysis, several inconsistent associations of perinatal mortality with the selected socio-demographic variables were observed in the primary studies level, both DHS and small scale studies. However, the overall odds ratio (OR) demonstrated statistically significant association of perinatal mortality with low maternal age (OR=1.2) and short birth interval (OR=1.4) but was not influenced by the mothers' residence, low educational level and household wealth index. Very consistently, the highest perinatal mortality rates reported when the birth intervals were either too short (<15 months) or too long (>39 months).
  
  
  CONCLUSIONS
  Because of the disagreement among previous studies, the present study demonstrated a small effect size on the increased risk of perinatal mortality among women who were pregnant during teenage ages and gave birth too frequently or after a long interval. Therefore, to confirm the strong predictors of perinatal mortality, further studies on sociodemographic factors are needed.
authors.affiliation: Hawassa University, College of Medicine and Health Sciences, Department of Gynecology-Obstetrics.
authors.forename: Yifru
authors.initials: Y
authors.lastname: Berhan
authors.affiliation: Hawassa University, College of Medicine and Health Sciences, Department of Pharmacology.
authors.forename: Asres
authors.initials: A
authors.lastname: Berhan
mesh_terms: D003906:Developing Countries; D005260:Female; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D066087:Perinatal Death; D054238:Perinatal Mortality; D011247:Pregnancy; D012959:Socioeconomic Factors; D050497:Stillbirth
keywords: birth interval; education; mother's age; perinatal mortality; subgroup meta-analysis