EFFECT OF LONG-TERM COCAINE ADMINISTRATION TO PREGNANT EWES ON FETAL HEMODYNAMICS, OXYGENATION, AND GROWTH

Objective: To assess uterine and fetal blood flows by Doppler velocime try and fetal growth and oxygenation in pregnant ewes treated daily wi th cocaine and to determine whether cocaine impairs fetal cardiac and cerebral reactivity. Methods: The study groups received 70 mg (n = 7) or 140 mg (n = 7) of cocaine and the control group (n = 7) received pl acebo injected intramuscularly daily on days 60-134. Hemodynamic data were measured at rest and during two acute hypoxic tests at cesarean d elivery performed on day 134. Results: The fetal heart rate (FHR) and umbilical and uterine resistance indices (RIs) were higher in the coca ine groups than in the control group (FHR: 187 +/- 8 and 166 +/- 8 bea ts per minute at 83 and 123 days, respectively, in controls and 9-11% higher in cocaine groups; umbilical RI: 0.79 +/- 0.06, 0.60 +/- 0.04, and 0.52 +/- 0.06, at 83, 105, and 123 days, respectively, in controls and 11-17% higher In the cocaine groups [P < .01]; and uterine RI: 0. 40 +/- 0.05, 0.40 +/- 0.04, and 0.37 +/- 0.04, at 83, 105, and 123 day s, respectively, in controls and 13-35% higher in cocaine groups [P < .05]). At delivery on day 134, the following characteristics were foun d to be different in the cocaine groups: fetal weight (4.03 +/- 0.2 kg in controls and 15-21% lower in the cocaine groups [P < .02]), partia l pressure of oxygen (26.5 +/- 1.4 mmHg in controls and 15-16% lower i n cocaine groups [P < .05]), umbilical RI (0.40 +/- 0.03 in controls a nd 11-17% higher in cocaine groups [P < .01]), cerebral RI (0.61 +/- 0 .03 in controls and 9-15% lower in cocaine groups [P < .01]), and cere bral-umbilical ratio (1.52 +/- 0.04 in controls and 22-23% lower in co caine groups [P < .001]). During the hypoxic tests, the cerebral RI (P < .05) and the cerebral-umbilical ratio (P < .05) decreased significa ntly less in the two cocaine groups. The FHR response was reduced sign ificantly in the two cocaine groups (P < .05). Conclusion: Long-term e xposure to cocaine induces uterine and fetal blood flow disorders, fet al growth restriction, and hypoxia. It reduces the capability of the c erebral vessels to vasodilate and the heart rate to increase during ac ute hypoxia. (C) 1997 by The American College of Obstetricians and Gyn ecologists.