Impact of abnormal results of outpatient fetal heart rate monitoring on maternal intervention in labor

OBJECTIVE: To conduct a retrospective, cohort study to determine the impact of abnormal outpatient fetal heart rate (FHR) testing on maternal interventions in labor, including labor induction, operative vaginal delivery and unplanned cesarean section. STUDY DESIGN: Our cohort consisted of 1,386 women with singleton gestations who had outpatient fetal nonstress testing within 1 week prior to giving birth between 1993 and 1998. Antepartum FHR records were interpreted as reassuring or nonreassuring, and pregnancy records were abstracted for background medical information, labor interventions and pregnancy outcomes. Logistic regression models were used to describe the association between abnormal outpatient monitoring results and maternal interventions in labor. RESULTS: After adjusting for potential confounders (maternal age, race, prior history of cesarean section, antepartum indications for monitoring, fetal presentation and abnormal fetal heart rate patterns in labor), women with nonreassuring monitoring were 90% more likely to undergo induction. The 2 groups were similar in operative vaginal delivery rates, but pregnancies with nonreassuring testing were more than twice as likely to end with an unplanned cesarean section. CONCLUSION: Abnormal outpatient antenatal FHR testing may be independently associated with an increased risk of unplanned cesarean section.