Relationship of early intrapartum fetal heart rate patterns to subsequent patterns and fetal outcome.

ABSTRACT

This study evaluated subsequent fetal heart rate (FHR) patterns and fetal outcome in laboring women with normal or abnormal initial FHR patterns. Four hundred term gravidas presenting in the latent phase of labor were studied. Ninety (22.5%) exhibited abnormalities on the initial tracing, with the majority of those abnormalities (58.9%) including mild variable decelerations, either alone or in combination with other abnormalities. An analysis of the outcome for those patients revealed a significant increase in cesarean delivery for fetal distress and depressed one-minute Apgar scores when compared to patients with initially normal tracings. Analysis of subsequent FHR patterns in that group showed a significant increase in the incidence of atypical variable declerations and bradycardia. Patients with more than one abnormality on the initial FHR tracing showed a greater incidence of loss of variability, loss of reactivity and bradycardia on subsequent FHR tracings. Likewise, pregnancy outcome for this group was remarkable for an increased risk of meconium staining, cesarean delivery for fetal distress and depressed one-minute Apgar scores. An abnormal initial FHR tracing seems to be associated with the subsequent development of ominous FHR patterns and increased fetal morbidity, particularly when more than one abnormality is present on the initial tracing.