Human umbilical vessels: Responses to agents frequently used in obstetric patients

Michael A. Belfort, George R. Saade, Maya Suresh, David Johnson, Yuri P. Vedernikov

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


OBJECTIVE: Our purpose was to study the effects of some drugs frequently used in pregnant women on isolated human umbilical artery and vein segments. STUDY DESIGN: Umbilical artery and vein rings from normal term pregnancies were mounted in Krebs-bicarbonate solution in organ baths for isometric tension recording. Rings were contracted with potassium chloride (60 mmol/L) or U46619 (10-8 mol/L) and then exposed to cumulative concentrations of nimodipine, nifedipine, nicardipine, phenytoin, magnesium sulfate, and hydralazine. Concentration-response curves were constructed by means of the difference in the percent relaxation between test and control vessels. Data analysis was by repeated measures analysis of variance, Newman-Keuls test, and the unpaired Student t test as appropriate. A value of p < 0.05 was considered statistically significant. RESULTS: All the agents studied were effective umbilical vasodilators, excet for hydralazine, which had minimal effect. The dihydropyridine calcium antagonists were more potent vasodilators than were the other agents studied. Nifedipine was the most potent calcium blocker and was the only dihydropyridine that relaxed the umbilical vein to a greater extent than the umbilical artery. CONCLUSION: The most commonly used drugs in preeclampsia have variable effects on the umbilical vessels.

Original languageEnglish (US)
Pages (from-to)1395-1403
Number of pages9
JournalAmerican journal of obstetrics and gynecology
Issue number5
StatePublished - May 1995
Externally publishedYes


  • Umbilical vessels
  • dihydropyridines
  • hydralazine
  • magnesium sulfate
  • phenytoin

ASJC Scopus subject areas

  • Obstetrics and Gynecology


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