Fetal responses to maternal infusions of angiotensin II

Alfredo J. Perales, Raymond P. Naden, Abbot Laptook, Charles R. Rosenfeld

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

It is unclear whether the fetus is affected by maternal infusions of angiotensin II; therefore we studied maternal and fetal responses (n = 9) to angiotensin II (1.15, 2.29, 11.5 μg/min) infused 5 minutes into the vena cava of chronically instrumented sheep (129 to 137 days of gestation) while monitoring Po2, Pco2, pH heart rate, uterine blood flow, and arterial and umbilical venous pressures. Pregnant sheep demonstrated expected dose-related increases in mean arterial pressure and decreases in uterine blood flow (p < 0.05). Increases in fetal mean arterial pressure also correlated with the maternal dose of angiotensin II (r = 0.77, p < 0.001). Fetal heart rate appeared to increase with 2.29 μg/min; however, bradycardia was observed with 11.5 μg/min (p < 0.05) and was associated with decreased PaO2, 19.0 ± 1.0 to 14.3 ± 1.4 mm Hg (p, 0.05), increased PaO2 (p < 0.05), and decreased umbilical venous Po2, 31.4 ± 2.3 to 27.0 ± 27.0 ± 1.9 mm Hg. The decreases in Po2 correlated with decreases in uterine blood flow (r = 0.60, p < 0.002, and r = 0.75, p < 0.005, respectively). Nevertheless, changes in fetal mean arterial pressure also occurred in the absence of altered fetal oxygenation; thus decreased uterine blood flow and fetal oxygenation alone cannot explain the fetal cardiovascular responses. It is suggested that angiotensin II or an active metabolite may cross the ovine placenta.

Original languageEnglish (US)
Pages (from-to)195-203
Number of pages9
JournalAmerican journal of obstetrics and gynecology
Volume154
Issue number1
DOIs
StatePublished - Jan 1986

Keywords

  • Uterine blood flow
  • angiotensin II
  • fetal oxygenation
  • fetus

ASJC Scopus subject areas

  • Obstetrics and Gynecology

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