What is the interpretation of fetal heart tracings (FHTs) showing Category II with repetitive late decelerations, moderate variability, and accelerations, indicating an overall reactive and reassuring pattern?

From the Guidelines

Category II fetal heart tracings with prolonged deceleration, but overall reactive with moderate variability, do not necessitate immediate delivery, and management should focus on close monitoring and addressing potential causes of the deceleration. The presence of moderate variability and reactivity in the tracing are reassuring signs that suggest adequate fetal oxygenation despite the deceleration 1. The management approach should include:

• Continuous electronic fetal monitoring to closely observe any changes in the fetal heart rate pattern
• Maternal position changes, particularly left lateral positioning, to improve uteroplacental perfusion
• Oxygen administration at 10L/min via face mask if needed, to ensure adequate maternal oxygenation
• Discontinuation of oxytocin if being administered, as it may be contributing to the deceleration
• Consideration of an intravenous fluid bolus (500-1000mL of lactated Ringer's solution) to address potential maternal hypotension The prolonged deceleration may be caused by cord compression, placental insufficiency, or maternal hypotension, so addressing these potential causes is important 1. If the tracing doesn't improve within 30 minutes or deteriorates to Category III, preparation for expedited delivery may be necessary. Documentation of interventions and the fetal response is essential for ongoing management decisions. The NICHD guidelines support a three-category system for interpreting fetal heart rate tracings, and Category II tracings, such as this one, require increased frequency of interventions and close monitoring 1.

From the Research

Fetal Heart Rate Tracings

• Fetal heart rate tracings are used to assess fetal well-being during labor, with different categories indicating varying levels of concern 2
• Category II tracings, such as the one described, indicate a non-reassuring fetal status, but with some compensatory mechanisms still present 2
• The presence of moderate variability and accelerations in the tracing suggests that the fetus is still able to mount some compensatory responses to stress 2

Decelerations

• Decelerations in fetal heart rate tracings can be a sign of fetal distress, but can also be caused by other factors such as umbilical cord compression 3
• The type and severity of decelerations can provide information about the underlying cause of the fetal distress 3
• In this case, the presence of prolonged decelerations is concerning, but the overall reactive and reassuring pattern of the tracing suggests that the fetus is still able to compensate for the stress 2

Clinical Context

• The clinical context, including the progress of labor, fetal size and reserves, and presence of meconium staining or intrauterine inflammation, is important in interpreting fetal heart rate tracings 2
• The use of amnioinfusion or other interventions may be considered in cases where fetal distress is suspected, but the decision to intervene should be based on a thorough evaluation of the clinical context and the fetal heart rate tracing 3, 4

Management

• The management of fetal heart rate tracings should be individualized, taking into account the specific characteristics of the tracing and the clinical context 2
• The use of terbutaline or other medications may be considered in cases where fetal distress is suspected, but the effects of these medications on the fetal heart rate should be carefully monitored 5