To determine if there are any specific monitoring patterns associated with chromosomal abnormalities the intrapartum tracings of 17 postnatally diagnosed karyotypically abnormal infants were obtained. Controls were randomly selected from infants born on the same day at the same gestational age. The tracings from these two groups were independently evaluated. Comparison of the monitor interpretations showed: (1) the karyotypically abnormal group was more likely to have decreased or absent short- (p < 0.001) and long-term (p < 0.01) variability; (2) accelerations were more likely to be represented in the control group (p < 0.001); (3) no significant differences were found in the baseline heart rates or in the presence or frequency of mild, moderate, or severe variable or late decelerations. These findings may reflect underlying central nervous system abnormalities as opposed to uteroplacental insufficiency, but are not specific to karyotypically abnormal infants.