EFFECT OF MATERNAL COCAINE ABUSE ON RENAL ARTERIAL FLOW AND URINE OUTPUT OF THE FETUS

OBJECTIVE: Our purpose was to study the short-term effect of maternal cocaine abuse on blood flow of the fetal kidney and the fetal hourly u rine output. STUDY DESIGN: Thirty-three pregnant patients of various g estational ages with a history of cocaine abuse were studied. Patients were included if the urine specimen was positive for cocaine on the d ay of study. Patients were excluded if the urine specimen was positive for any other vasoactive substances or medications. Color and pulsed wave Doppler studies were used to obtain the flow velocity waveform of the fetal renal artery. The resistance index was calculated from syst olic and diastolic values of flow velocity waveforms, Longitudinal, tr ansverse, and anteroposterior diameters of the fetal urinary bladder w ere measured from transverse and coronal images at their maximum diame ters, and the bladder volume was calculated. The hourly urine output o f the fetus was measured from the difference in the bladder volume al half-hour intervals. As controls, 110 normal pregnancies between 19 an d 40 weeks were similarly studied for normal values. The resistance in dex of the fetal renal artery and the hourly fetal urine output of the two groups were compared. RESULTS: The resistance index of the fetal renal artery of normal pregnancies had a negative association with ges tational age (p < 0.05). Cocaine-exposed fetuses had a significantly h igher resistance index of the renal artery (p < 0.01) than did normal fetuses of corresponding gestational ages. A decrease in the hourly ur ine output of cocaine-exposed fetuses was observed, compared with norm al controls of corresponding gestational ages (p < 0.001). CONCLUSION: The resistance index values of fetal renal artery and fetal urine out put were affected by maternal cocaine abuse.