title: The effect of maternal hypertension on mortality in infants 22, 29weeks gestation.
abstract: OBJECTIVE
  To evaluate the effect of maternal hypertension on mortality risk prior to discharge, in infants 22+0 to 29+6weeks gestational age.
  
  
  METHODS
  We evaluated 88,275 North American infants whose births were recorded in Vermont Oxford Network centers between 2008 and 2011 Infants born between 22+0 and 29+6weeks gestational age were evaluated in 2-week gestational age cohorts and followed until death or discharge. Logistic regression was used to adjust for birth weight, antenatal steroid exposure, infant sex, maternal race, inborn/outborn, prenatal care and birth year.
  
  
  RESULTS
  21,896 infants were born to hypertensive mothers; 13% died prior to Neonatal Intensive Care Unit discharge compared to 20% of the 66,379 infants born to mothers without hypertension. After adjustment, infants had significantly lower mortality compared to preterm infants not born to hypertensive mothers, at all gestational ages examined (22/23: odds ratio (OR)=0.65 (95% Confidence Interval (CI): 0.55, 0.77; 24/25); OR=0.77 (95% CI: 0.71, 0.84); 26/27: OR=0.66 (95% CI: 0.59, 0.74); 28/29: OR=0.58 (95% CI: 0.51, 0.67). Additionally, births associated with maternal hypertension increase dramatically by gestational age, resulting in a larger proportion of births associated with maternal hypertension at later gestational ages.
  
  
  CONCLUSIONS
  Preterm birth due to any cause carries significant risk of mortality, especially at the earliest of viable gestational ages. Maternal hypertension independently influences mortality, with lower odds of mortality seen in infants born to hypertensive mothers, after adjustment, and should be taken into consideration as an element in counseling parents.
authors.affiliation: University of Vermont, Department of Obstetrics, Gynecology and Reproductive Sciences, Burlington, VT 05405, United States. Electronic address: carole.mcbride@med.uvm.edu.
authors.forename: Carole A
authors.initials: CA
authors.lastname: McBride
authors.affiliation: University of Vermont, Department of Obstetrics, Gynecology and Reproductive Sciences, Burlington, VT 05405, United States; Vermont Oxford Network, Burlington, VT 05401, United States.
authors.forename: Ira M
authors.initials: IM
authors.lastname: Bernstein
authors.affiliation: University of Vermont, Department of Medical Biostatistics, Burlington, VT 05405, United States.
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Badger
authors.affiliation: University of Vermont, Department of Pediatrics, Burlington, VT 05405, United States; Vermont Oxford Network, Burlington, VT 05401, United States.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Horbar
authors.affiliation: University of Vermont, Department of Pediatrics, Burlington, VT 05405, United States; Vermont Oxford Network, Burlington, VT 05401, United States.
authors.forename: Roger F
authors.initials: RF
authors.lastname: Soll
mesh_terms: D000328:Adult; D005260:Female; D005865:Gestational Age; D006801:Humans; D006973:Hypertension / Q000453:epidemiology*; D015994:Incidence; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D007234:Infant, Premature; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data; D054238:Perinatal Mortality; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000453:epidemiology*; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D047928:Premature Birth / Q000401:mortality; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
keywords: Hypertension; Infant; Mortality; Preeclampsia; Premature