OBJECTIVE: Our aim was to evaluate the cardiovascular effects of high-dose intravaginal misoprostol administration by means of transthoracic electrical bioimpedance monitoring. STUDY DESIGN: Healthy women undergoing mid trimester pregnancy interruption with intravaginal misoprostol were eligible for this prospective observational study. Baseline blood pressure was obtained for 1 hour and transthoracic electrical bioimpedance monitoring was performed before misoprostol administration, 600 μg vaginally. Posttreatment assessments were made every 15 minutes for a total of 4 hours, with patients in a left lateral recumbent position. Heart rate, mean arterial pressure, cardiac index, stroke index, systemic vascular resistance index, and end-diastolic volume index were determined. Measurements were averaged for 30-minute intervals and reported as mean ± SD. Statistical analyses included the paired t test and repeated-measures analysis of variance. RESULTS: Nine women consented to have transthoracic electrical bioimpedance monitoring, and no statistically significant changes in any of the measured cardiac parameters for the 4-hour monitoring interval were noted. Direct comparisons between the pretreatment and 2-hour posttreatment intervals (reported time peak of blood misoprostol levels) also revealed no significant differences in the cardiovascular index values. CONCLUSION: High-dose intravaginal misoprostol in the mid trimester does not alter maternal cardiac function as measured by transthoracic electrical bioimpedance.