title: Effects of oral L-arginine on the pulsatility indices of umbilical artery and middle cerebral artery in preterm labor.
abstract: OBJECTIVE
  The objective of the study was the estimation of the influence of oral supplementation with low-dose l-arginine on feto-placental circulation in women with threatened preterm labor.
  
  
  METHODS
  Oral administration of 3g of L-arginine daily or placebo as a supplement to standard tocolytic therapy was tried in 70 women with threatened preterm delivery, randomly assigned to the L-arginine (n=37) or placebo (n=33) groups. Twenty-five and 20 completed the study, respectively. Doppler velocimetry of pulsatility indices (PI) of the umbilical (UA) and middle cerebral (MCA) arteries as well as pregnancy outcome and biochemical markers of nitric oxide synthesis (plasma amino acid and nitrite/nitrate levels, as well as 24 h nitrite/nitrate excretion with urine) were estimated.
  
  
  RESULTS
  Starting from the second week of therapy, the UA PI values were significantly lower in the L-arginine group than in the placebo group. Moreover, treatment with L-arginine caused a significant increase in MCA PI and cerebro-placental ratio (CPR) values. The changes in feto-placental circulation in the L-arginine group were not associated with any signs of increased nitric oxide synthesis.
  
  
  CONCLUSIONS
  Oral supplementation with low doses of L-arginine changed feto-placental blood flow distribution in patients with threatened preterm labor. The exact mechanism of L-arginine action on feto-placental circulation requires further investigation.
authors: Department of Gynecology and Obstetrics, Jagiellonian University Medical College, Kraków, Poland. morytlew@cyf-kr.edu.pl
authors: Krzysztof
authors: K
authors: Rytlewski
authors: Rafal
authors: R
authors: Olszanecki
authors: Ryszard
authors: R
authors: Lauterbach
authors: Anna
authors: A
authors: Grzyb
authors: Beata
authors: B
authors: Kiec-Wilk
authors: Aldona
authors: A
authors: Dembinska-Kiec
authors: Antoni
authors: A
authors: Basta
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001120:Arginine / Q000008:administration & dosage*; D001783:Blood Flow Velocity; D002317:Cardiovascular Agents / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D020768:Middle Cerebral Artery / Q000187:drug effects* / Q000503:physiopathology; D009569:Nitric Oxide / Q000096:biosynthesis; D007752:Obstetric Labor, Premature / Q000378:metabolism*; D021041:Placental Circulation / Q000187:drug effects*; D011247:Pregnancy; D011256:Pregnancy Outcome; D014469:Umbilical Arteries / Q000187:drug effects* / Q000503:physiopathology
chemical_list: D002317:Cardiovascular Agents; D009569:Nitric Oxide; D001120:Arginine