Cardiovascular effects of cocaine in neonates exposed prenatally

This blinded cross-sectional study was to determine whether chronic cocaine exposure in utero produces abnormalities in left ventricular function (shortening fraction), heart rate, rhythm, and conduction in term neonates. Three groups of neonates were evaluated by two-dimensional echo Doppler and 24 hour Holter monitor, with studies initiated in the first 24 hours of life. Group A (n = 32) neonates had a positive history of chronic maternal cocaine use in pregnancy (MCU+) and a positive neonatal urine cocaine test (NUC+). Group B (n = 23) neonates were MCU+ but NUC-. Group C (n = 32) neonates were MCU- and NUC-. Measured parameters were compared statistically by analysis of variance. p < 0.05 was regarded as significant. Echocardiography showed no significant difference between groups A, B, and C for left ventricular shortening fraction. Holter monitor likewise revealed no significant difference between groups in minimal, maximal, and average heart rate, or in the incidence of supraventricular and ventricular arrhythmias greater than 20 beats/h in the 24-hour period. None of the patients had atrioventricular or bundle branch block. It is possible that the developmental state of the newborn heart makes it less responsive to the adverse effects of cocaine.