title: The cost of prematurity: a case-control study of twins vs singletons.
abstract: OBJECTIVE
  This study evaluated the extent to which morbidity and costs at birth were associated with plurality, gestational age, and birth-weight with a sample of twins from a large urban hospital.
  
  
  METHODS
  Each twin infant was matched to two singleton infants (control [ctrl]-singletons) for payor status and race, and to one singleton infant (gestation [ga]-singleton) for payor status, race, and gestational age; after exclusion of infants who were transferred, the study population included 111 twins, 242 ctrl-singletons, and 106 ga-singletons. Data were stratified by five gestational categories and compared across study groups. Outcomes included birthweight, neonatal diagnoses, infant length of stay, infant costs per day, and total infant and total birth costs.
  
  
  RESULTS
  Total birth costs ranged from $280,146 at 25 to 27 weeks to $9,803 at 39 to 42 weeks, decreasing with advancing gestation to means of $88,891 (twins), $43,041 (ga-singletons), and $9,326 (ctrl-singletons). Twins did not differ from either group of singletons in prematurity-related diagnoses, length of stay, or costs until after 34 weeks' gestation.
  
  
  CONCLUSIONS
  In this sample, prematurity, not plurality, was the predominant cost factor at birth. Compared with singletons, twins experienced increased morbidity and associated costs after 38 weeks' gestation.
authors.affiliation: Department of Obstetrics and Gynecology, University of Michigan Medical School, Ann Arbor, 48109, USA.
authors.forename: B
authors.initials: B
authors.lastname: Luke
authors.forename: H R
authors.initials: HR
authors.lastname: Bigger
authors.forename: S
authors.initials: S
authors.lastname: Leurgans
authors.forename: D
authors.initials: D
authors.lastname: Sietsema
mesh_terms: D001724:Birth Weight; D016022:Case-Control Studies; D002641:Chicago; D005260:Female; D005865:Gestational Age; D006302:Health Services Research; D017721:Hospital Costs / Q000706:statistics & numerical data*; D006801:Humans; D007231:Infant, Newborn; D015931:Intensive Care, Neonatal / Q000191:economics*; D007902:Length of Stay / Q000191:economics; D009017:Morbidity; D007752:Obstetric Labor, Premature / Q000150:complications / Q000191:economics*; D009775:Obstetrics and Gynecology Department, Hospital / Q000191:economics*; D011247:Pregnancy; D014427:Twins