From the Guidelines
Category III fetal heart rate (FHR) tracings necessitate immediate intervention, which often involves expedited delivery via operative vaginal or Cesarean delivery, as indicated by the National Institute of Child Health and Human Development (NICHD) guidelines 1. When a Category III tracing is identified, it signifies significant fetal compromise, and prompt action is required to prevent adverse outcomes. The characteristics of a Category III tracing include absent baseline FHR variability with recurrent late or variable decelerations and/or bradycardia, or with a sinusoidal pattern, as defined by the NICHD 1. Key steps in managing Category III tracings include:
- Discontinuing oxytocin (Pitocin) to avoid exacerbating fetal distress
- Expediting delivery, with the choice between operative vaginal delivery and Cesarean section depending on factors such as cervical dilation, fetal head station, maternal pelvic adequacy, and the estimated time to delivery
- Implementing general measures like vaginal examination, checking maternal vital signs, giving oxygen, changing maternal position, administering intravenous fluids, and assessing fetal pH with acoustic or fetal scalp stimulation, as outlined in the ALSO course using the DR C BRAVADO approach 1. The primary goal in the management of Category III FHR tracings is to ensure the safest and most expedient delivery method to prevent fetal morbidity and mortality, while also considering the mother's health and well-being. Given the potential for significant fetal hypoxemia and acidemia associated with Category III tracings, cesarean section is typically indicated if vaginal delivery is not imminent, emphasizing the need for a prompt and informed decision-making process in the clinical setting 1.
From the Research
Category III Fetal Heart Rate Tracings and Delivery
- Category III fetal heart rate (FHR) tracings are considered non-reassuring and may require immediate intervention 2
- The National Institute of Child Health and Human Development guidelines classify FHR tracings into three categories, with Category III being the most concerning 3, 2
- A study published in the Journal of obstetrics and gynaecology Canada found that implementation of a code blue protocol for emergency cesarean delivery due to Category III FHR tracings resulted in a decision-to-delivery interval of less than 30 minutes in 96.9% of cases 2
- The same study found that the incidence of stillbirth was higher in the group with a decision-to-delivery interval greater than 30 minutes, highlighting the importance of prompt intervention in cases of Category III FHR tracings 2
Operative Vaginal or Cesarean Delivery
- Category III FHR tracings may require operative vaginal or cesarean delivery, depending on the individual case and the healthcare provider's judgment 2, 4
- A study published in the American journal of obstetrics and gynecology found that the use of fetal pulse oximetry in the evaluation of abnormal FHR patterns in labor improved the accuracy of fetal assessment and allowed for a safe reduction in cesarean deliveries performed due to non-reassuring fetal status 4
- However, the same study found that the overall cesarean delivery rate did not decrease, due to an increase in cesarean deliveries performed due to dystocia 4
- Another study published in Obstetrics and gynecology found that intrapartum resuscitation interventions, such as maternal oxygen and intravenous fluid bolus, can improve Category II FHR tracings and reduce the need for cesarean delivery 5