Is continuous monitoring the answer to incidentally observed fetal heart rate decelerations?

Objective: We examined the interventions and outcomes of pre-term patients with an incidentally identified fetal heart rate (FHR) deceleration and otherwise reassuring FHR pattern admitted for continuous FHR monitoring (FM).

Methods: A case series was compiled of patients with at least 36 h of continuous FM secondary to a FHR deceleration. Data on demographics, delivery and perinatal outcomes, medical and obstetric history were extracted from medical records. FHR tracings were reviewed for quantity and type of decelerations.

Results: Ninety-seven patients met inclusion criteria. The median length of time monitored was 4 days with a median of four decelerations a day. Fifty-eight percent of patients were delivered during the same admission primarily for a non-reassuring FHR tracing with a mean delivery gestational age of 33.7 weeks. Patients with resolution of their decelerations delivered at a mean gestational age of 35.8 weeks. No patients with a resolution of decelerations presented later with an intrauterine fetal demise.

Conclusion: Although it is possible that FHR decelerations were markers for adverse outcomes, none of the infants delivered for decelerations had an abnormal cord gas. Because it may lead to pre-term delivery based on false positive testing, clinicians should use caution when prescribing prolonged FM.