title: Induced termination of pregnancy and low birthweight and preterm birth: a systematic review and meta-analyses.
abstract: BACKGROUND
  History of induced termination of pregnancy (I-TOP) is suggested as a precursor for infant being born low birthweight (LBW), preterm (PT) or small for gestational age (SGA). Infection, mechanical trauma to the cervix leading to cervical incompetence and scarred tissue following curettage are suspected mechanisms.
  
  
  OBJECTIVE
  To systematically review the risk of an infant being born LBW/PT/SGA among women with history of I-TOP.
  
  
  METHODS
  Medline, Embase, CINAHL and bibliographies of identified articles were searched for English language studies.
  
  
  METHODS
  Studies reporting birth outcomes to mothers with or without history of induced abortion were included.
  
  
  METHODS
  and analyses Two reviewers independently collected data and assessed the quality of the studies for biases in sample selection, exposure assessment, confounder adjustment, analytical, outcome assessments and attrition. Meta-analyses were performed using random effect model and odds ratio (OR), weighted mean difference and 95% confidence interval (CI) were calculated.
  
  
  RESULTS
  Thirty-seven studies of low-moderate risk of bias were included. A history of one I-TOP was associated with increased unadjusted odds of LBW (OR 1.35, 95% CI 1.20-1.52) and PT (OR 1.36, 95% CI 1.24-1.50), but not SGA (OR 0.87, 95% CI 0.69-1.09). A history of more than one I-TOP was associated with LBW (OR 1.72, 95% CI 1.45-2.04) and PT (OR 1.93, 95% CI 1.28-2.71). Meta-analyses of adjusted risk estimates confirmed these findings.
  
  
  CONCLUSIONS
  A previous I-TOP is associated with a significantly increased risk of LBW and PT but not SGA. The risk increased as the number of I-TOP increased.
authors.affiliation: Department of Paediatrics, Mount Sinai Hospital, Toronto, ON, Canada. pshah@mtsinai.on.ca
authors.forename: P S
authors.initials: PS
authors.lastname: Shah
authors.forename: J
authors.initials: J
authors.lastname: Zao
mesh_terms: D000028:Abortion, Induced / Q000009:adverse effects / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D007236:Infant, Small for Gestational Age; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology* / Q000209:etiology; D018570:Risk Assessment