title: Risks in triplet pregnancy: advanced maternal age, premature rupture of membranes and risk estimates of mortality.
abstract: OBJECTIVE
  To investigate the impact of older maternal age on the risk of mortality associated with premature rupture of membranes (PROM) among triplets.
  
  
  METHODS
  A retrospective, cohort study was performed on triplet deliveries in the United States that occurred in the period perinatal and 1995-1998. The study group comprised mothers aged > or =40 years (older mothers), who were compared to mothers aged 30-39 (mature mothers), 20-29 (younger mothers) and mothers <20 (teenagers). We computed risks of mortality associated with PROM within each maternal age category using generalized estimating equations to take into account both intracluster and intercluster sources of variation.
  
  
  RESULTS
  The risk of stillbirth and of neonatal and perinatal mortality related to PROM was highest among teenagers. In all circumstances, the risk of both intrauterine and extrauterine death resulting from PROM diminished progressively with increasing maternal age until age 40 and beyond, at which point the risk rose once more and produced a U shape. PROM triplets of older mothers had apparently higher mortality indices than did those of younger and mature mothers, although the risk difference did not show statistical significance for any of the mortality indices. Similarly, the proportion of preventable deaths if PROM could be averted demonstrated a U-shape, consistent with that of risk estimates.
  
  
  CONCLUSIONS
  Premature rupture of membranes was associated with an increase risk of perinatal and infant mortality among triplets. Although older mothers demonstrated higher risk levels for all mortality indices in comparison to younger and mature mothers, our findings did not reach statistical significance.
authors.affiliation: Department of Epidemiology, University of Alabama at Birmingham, 1665 University Boulevard, Room 320, Birmingham, AL 35294, USA. hsalihu@uab.edu
authors.forename: Muktar H
authors.initials: MH
authors.lastname: Aliyu
authors.forename: Hamisu M
authors.initials: HM
authors.lastname: Salihu
authors.forename: Mary L
authors.initials: ML
authors.lastname: Blankson
authors.forename: Greg R
authors.initials: GR
authors.lastname: Alexander
authors.forename: Louis
authors.initials: L
authors.lastname: Keith
mesh_terms: D000293:Adolescent; D000367:Age Factors; D015331:Cohort Studies; D005260:Female; D005313:Fetal Death / Q000453:epidemiology* / Q000209:etiology; D005322:Premature Rupture of Fetal Membranes / Q000150:complications / Q000401:mortality; D006801:Humans; D007231:Infant, Newborn; D008423:Maternal Age; D015999:Multivariate Analysis; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D014310:Triplets; D014481:United States / Q000453:epidemiology