SIGNIFICANCE OF SPORADIC DECELERATION DURING ANTEPARTUM TESTING IN TERM PREGNANCIES

We have investigated the significance of single sporadic deceleration during reactive nonstress testing in normal pregnancies at term. A pro spective study was performed during a 1-year period including 4742 non stress tests performed between the 38th and 42nd weeks of pregnancy in patients referred to our department for antepartum testing and withou t any complication or pathology. Nonstress test (NST) was carried out with the patient lying on her left side, and was defined as reactive i f at least two accelerations of 15 beats/min (bpm) or more lasting 15 sec were observed in a 20-min period. Sporadic deceleration was define d as a decrease in the fetal heart rate to less than 90 bpm or a decre ase of 40 bpm below the baseline, lasting at least 2 min. The sporadic deceleration was considered as single when only one appeared in the f irst 20 min of monitoring and repeated when observed again once in at least one subsequent monitoring. Thirty-four cases of single sporadic deceleration were observed among women with reactive NST. In 14 cases there were repeated sporadic decelerations. The patients were divided into two groups according to the presence or absence of repeated decel erations. Outcomes of patients with repeated sporadic decelerations we re compared with a group of 34 patients where sporadic decelerations w ere not observed during the antepartum testing. A significantly higher percentage of pathological fetal heart rate traces during labor were observed in the group of repeated decelerations. In conclusion the pre sence of repeated sporadic decelerations during a reactive NST suggest s that the cause of cord compromise is persistent and recurrent cord c ompression is possible. Therefore, in these cases an increased fetal r isk could be expected.