VASOACTIVE DRUGS IN OBSTETRICS - A REVIEW OF DATA OBTAINED BY DOPPLER AND COLOR DOPPLER METHODS

Objective: We did a literature review of the hemodynamic effects of different vasoactive agents, as assessed by Doppler and color Doppler methods. Methods: The review included reports dealing with the Doppler method assisted by basic ultrasound real-time, M-mode, and color Doppler techniques. Results and Conclusions: Maternal vasoactive drugs (labetalol, dihydralazine, pindolol, nifedipine), anesthesia, and maternal position do not hinder the uteroplacental and fetal circulation to the extent that clinical complications would ensue. However, if these factors are strong enough, an increased vascular resistance in the uterine arteries does appear without any immediate compromises in fetal hemodynamics. Some regulatory changes do occur, however, in the fetal cerebral and renal arteries and in fetal myocardial contractility. This signifies that some vasoactive drugs may compromise fetal hemodynamics, especially in fetuses with poor blood or oxygen supply before treatment. One good example of the fetal hemodynamic changes caused by maternal drug is the vasoconstriction of fetal ductus arteriosus during maternal intake of indomethacin, and demonstrated by the Doppler technique. The circulatory safety of both routinely used vasoactive agents and new drugs can now be tested with the Doppler method more reliably than before. Increased understanding of uterine and fetal hemoodynmic regulation in many different clinical conditions and their treatment schedules has benefited perinatal practice.