ABSTRACT
We have investigated the significance of single sporadic deceleration during reactive
nonstress testing in normal pregnancies at term. A prospective study was performed
during a 1-year period including 4742 nonstress tests performed between the 38th and
42nd weeks of pregnancy in patients referred to our department for antepar-tum testing
and without any complication or pathology. Nonstress test (NST) was carried out with
the patient lying on her left side, and was defined as reactive if at least two accelerations
of 15 beats/min (bpm) or more lasting 15 sec were observed in a 20-min period. Sporadic
deceleration was defined as a decrease in the fetal heart rate to less than 90 bpm
or a decrease of 40 bpm below the baseline, lasting at least 2 min. The sporadic deceleration
was considered as single when only one appeared in the first 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 decelerations. Outcomes
of patients with repeated sporadic decelerations were compared with a group of 34
patients where sporadic decelerations were 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 presence of
repeated sporadic decelerations during a reactive NST suggests that the cause of cord
compromise is persistent and recurrent cord compression is possible. Therefore, in
these cases an increased fetal risk could be expected.
Keywords
Sporadic deceleration - nonstress testing - cord complication - term pregnancies
