From the Guidelines
Late decelerations during fetal monitoring require immediate intervention to improve uteroplacental perfusion and fetal oxygenation. First, reposition the mother to her left side to relieve pressure on the inferior vena cava and increase blood flow to the placenta 1. Administer supplemental oxygen at 8-10 L/min via face mask to the mother to improve oxygen delivery to the fetus. Stop any oxytocin infusion if in use, as it may be causing excessive uterine contractions. Provide intravenous fluid bolus (500-1000 mL of lactated Ringer's or normal saline) to improve maternal blood pressure and placental perfusion. If hypotension is present, consider vasopressors like ephedrine (5-10 mg IV) or phenylephrine (50-100 mcg IV). For persistent late decelerations, prepare for possible emergency delivery, as they indicate uteroplacental insufficiency where the fetus becomes hypoxic during contractions and doesn't recover until after the contraction ends. This pattern suggests the placenta cannot maintain adequate oxygen transfer during the stress of contractions, which can lead to fetal acidosis if not corrected. Notify the obstetric provider immediately while implementing these measures, as late decelerations represent a concerning pattern that may require prompt delivery depending on the clinical context and gestational age 1.
Some key points to consider when managing late decelerations include:
- The presence of spontaneous repetitive late decelerations is accepted as an indication for delivery in viable pregnancies with fetal growth restriction, irrespective of Doppler findings 1.
- Intrauterine resuscitation interventions, such as discontinuing oxytocin and administering maternal oxygen, may be beneficial in improving fetal oxygenation 1.
- The use of tocolytic agents, such as terbutaline, may be considered to transiently stop contractions, but their effectiveness in improving neonatal outcomes is limited 1.
Overall, the management of late decelerations should prioritize improving uteroplacental perfusion and fetal oxygenation, and preparing for possible emergency delivery if the pattern persists.
From the Research
Treatment of Late Decelerations
To treat late decelerations, the following steps can be taken:
- Identify and address any underlying reversible causes, such as maternal hypotension, uterine hypertonus or hyperstimulation, and sustained umbilical cord compression 2
- Implement immediate conservative measures, also known as intrauterine fetal resuscitation, to reverse the underlying cause of acute and profound reduction in fetal oxygenation 2
- Administer maternal oxygen to increase fetal oxygenation, especially in the presence of variable decelerations 3, 4
- Consider acute tocolysis to rapidly restore fetal oxygenation in cases of uterine hypertonus or hyperstimulation 2
Monitoring and Assessment
- Continuously monitor fetal heart rate and oxygen saturation to assess the effectiveness of treatment 2, 3
- Perform regular clinical audits to identify organizational and system issues that may contribute to poor perinatal outcomes 2
- Use tools such as fetal scalp blood sampling and transcutaneous PO2 measurement to estimate the degree of fetal acidosis and predict fetal hazard 5
Important Considerations
- Late decelerations can be associated with normal outcomes if they are related to fetal breathing movements, and may not always require intervention 6
- The continuation of prolonged deceleration for more than 10 minutes can increase the risk of hypoxic-ischemic injury to the deep gray matter of the brain, and should be considered an intrapartum emergency requiring immediate intervention 2