title: The effect of low-dose aspirin on umbilical artery Doppler measurements.
abstract: OBJECTIVE
  Our purpose was to determine if the maternal administration of low-dose (60 mg) aspirin from 24 weeks' gestation until delivery is associated with significant changes in longitudinal umbilical artery Doppler index values.
  
  
  METHODS
  Healthy, young nulliparous women with singleton gestations who were enrolled in a double-blind trial of low-dose aspirin for preeclampsia prevention underwent prerandomization and monthly postrandomization continuous-wave umbilical artery Doppler evaluations. The systolic-to-diastolic ratio and the resistance index were determined at each examination. Compliance with the medical regimen was assessed by pill counts and measurement of maternal serum thromboxane B2 levels.
  
  
  RESULTS
  The prerandomization Doppler index values were similar between the two randomization groups in the 538 (aspirin 266, placebo 272) patients studied. We found no significant differences with univariate comparisons and multiple linear regression modeling in the postrandomization Doppler index values (p = 0.21 to 0.96). No differences were found when patients were assessed by randomization assignment group (intent to treat) or by biochemical evidence for compliance and absence of crossover with maternal serum thromboxane B2 levels.
  
  
  CONCLUSIONS
  The use of low-dose aspirin from 24 weeks' gestation until delivery does not significantly affect umbilical artery Doppler index values.
authors.affiliation: Department of Obstetrics and Gynecology, University of Alabama at Birmingham 35233-7333.
authors.forename: J
authors.initials: J
authors.lastname: Owen
authors.forename: J E
authors.initials: JE
authors.lastname: Maher
authors.forename: J C
authors.initials: JC
authors.lastname: Hauth
authors.forename: R L
authors.initials: RL
authors.lastname: Goldenberg
authors.forename: C R
authors.initials: CR
authors.lastname: Parker
mesh_terms: D001241:Aspirin / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D004311:Double-Blind Method; D005260:Female; D005333:Fetus / Q000098:blood supply*; D005500:Follow-Up Studies; D006801:Humans; D008431:Maternal-Fetal Exchange; D010349:Patient Compliance; D011247:Pregnancy / Q000097:blood; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D012044:Regression Analysis; D012212:Rheology; D013929:Thromboxane B2 / Q000097:blood; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000187:drug effects* / Q000502:physiology; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D013929:Thromboxane B2; D001241:Aspirin