Prevalence of fetal heart rate decelerations in self-referred low-risk patients in the third trimester.

We tested the hypotheses that fetal heart rate decelerations are present during the third trimester in most low risk pregnant women, the prevalence of decelerations is a function of the length of time fetal heart rate monitoring occurs and their presence is not associated with an adverse prognosis. We performed a retrospective chart review of 114 self-referred low-risk pregnant patients who presented to the labor and delivery triage area of a tertiary care hospital at 26-41 weeks gestation. None required admission to the hospital. The control group consisted of patients who delivered immediately before and after the delivery of the study patient. Normal long-term variability and fetal baseline heart rate were found in all electronic fetal monitoring tracings. Accelerations were present in 91% and decelerations in 65% of patients. There was no correlation between length of time of monitoring and the incidence of decelerations. At delivery, there were no differences in birthweight, gestational age, 5-min Apgar scores or cord pH between the control and study patients. Variable decelerations were a common finding in the third trimester of low-risk pregnant patients who self referred to labor and delivery triage. They were not prognostic of an adverse perinatal outcome.