The effect of angiotensin II on utero-placental and umbilical circulation in normotensive pregnant women.

OBJECTIVES

The angiotensin sensitivity test (AST) has been used to identify pregnant women likely to develop pre-eclampsia. The purpose of this study was to evaluate uteroplacental circulation and fetal response to angiotensin II (A-II).

METHODS

We studied blood flow velocity waveforms in the uterine and umbilical arteries of 23 normotensive pregnant women before, during and after the AST by Doppler ultrasonography. Fetal well-being was documented with biophysical profiles (BPS). ANOVA and two-way analysis of variation were used to analyze the results.

RESULTS

Infusion of A-II to normotensive pregnant women did not affect umbilical artery resistance at 20 or 30 weeks' gestation. Uterine artery resistance and maternal heart rate decreased significantly at 20 weeks' gestation with an AST-induced 10 mmHg or 20 mmHg rise in diastolic blood pressure. The BPS were not altered after the AST.

CONCLUSIONS

The AST does not increase vascular resistance in the uterine or umbilical circulation, and may be considered a safe procedure for both the mother and fetus.