Does station of the fetal head at epidural placement affect the position of the fetal vertex at delivery?

Abstract

OBJECTIVE: The objective of the study was to determine whether epidural placement before engagement of the fetal head is associated with an increase in the incidence of malposition at delivery. STUDY DESIGN: We performed a retrospective cohort study to ascertain the relation between station at epidural placement and malposition. Three hundred fifty-seven patient records were reviewed; 320 records of patients in spontaneous or induced labor who received epidural analgesia were included in the analysis. Patients with a contraindication to labor, antepartum fetal death, or twins were excluded. Maternal demographics, cervical examination at epidural placement, epidural medication characteristics, and labor and delivery data were abstracted from medical records. Station was characterized as high if the fetal vertex was above the level of the maternal ischial spines or low if the vertex was at or below the level of the ischial spines at the time of epidural placement. RESULTS: The relative risk of occiput malposition was significantly increased with epidural placement at high station. This risk remained after we controlled for age and birth weight. Cervical dilatation was not independently associated with occiput position at delivery. CONCLUSIONS: Epidural placement before engagement of the fetal head is associated with an increased incidence of malposition at delivery. This finding may provide an insight into the empiric observation that operative delivery is variably increased for patients laboring under epidural anesthesia. (Am J Obstet Gynecol 1996;175:991-4.)