What is the management of abnormal uterine contractions in Cardiotocography (CTG)?

Management of Abnormal Uterine Contractions on CTG

When abnormal uterine contractions are identified on CTG, the primary management depends on whether you're dealing with hypercontractility (excessive contractions) or hypocontractility (inadequate contractions), with hypercontractility requiring immediate intervention to prevent fetal compromise, while hypocontractility management remains controversial and should be approached cautiously.

Identifying Abnormal Contraction Patterns

Hypercontractility (Tachysystole)

• Hypercontractility can be successfully evaluated by simple palpation unless obesity prevents it 1
• Look for excessive frequency, duration, or intensity of contractions that may compromise fetal oxygenation
• Continuous CTG monitoring is essential when hypercontractility is suspected 1

Hypocontractility (Inadequate Contractions)

• The ability to distinguish between adequate and inadequate contractility has proved elusive, making selection of cases that would benefit from ecbolic drugs often not possible 1
• There is a very broad spectrum of uterine contractility patterns associated with both normal and dysfunctional labor patterns 1
• Quantitation of uterine activity via intrauterine pressure transducer is not useful in aiding decision-making about oxytocin administration or dosage 1

Management of Hypercontractility

Immediate Interventions

• Stop any uterotonic stimulation immediately, as uterotonic stimulation is inadvisable lest unsafe uterine hyperstimulation occurs 1
• Position the patient in left lateral position to ensure adequate venous return from the inferior vena cava 1
• Administer IV fluids cautiously while monitoring for fluid overload 1
• Consider tocolytics if fetal heart rate abnormalities accompany the hypercontractility

Monitoring Requirements

• Continuous cardiotocography monitoring of the fetus is mandatory 1
• For high-risk pregnancies with normal umbilical artery Doppler, CTG monitoring should be performed every 2 weeks 2
• For high-risk pregnancies with abnormal umbilical artery Doppler, CTG monitoring should be performed at least weekly 2
• For pregnancies with absent or reversed end-diastolic velocity, CTG monitoring should be increased to 1-2 times per day 2

Management of Hypocontractility

Conservative Approach

• Despite the appeal of using intrauterine pressure transducers to define adequacy of contractions, studies have failed to prove the virtue of this approach for diagnosis and treatment 1
• Assess labor progress through cervical examination rather than relying solely on contraction quantification 1
• Consider that many normal labor patterns exist with varying contraction patterns 1

Oxytocin Augmentation Considerations

• If oxytocin is used, administer as a slow IV infusion (<2 U/min) to avoid systemic hypotension while promoting uterine contraction 3
• Careful monitoring is required when any uterotonic is used due to potential hemodynamic effects 3
• Ergometrine is contraindicated 1, 3
• Methylergonovine is contraindicated due to significant risk of vasoconstriction and hypertension 3

Labor Management Principles

Positioning and Support

• The left lateral position ensures adequate venous return, but a sitting-up position may be needed for women in cardiac failure 1
• Epidural analgesia is preferred during labor as it stabilizes cardiac output 1

Second Stage Management

• The second stage of labor is a time of increased exertion and strong contractions, and prolonged bearing down efforts must be discouraged 1
• Where spontaneous delivery cannot be achieved rapidly, low forceps or vacuum-assisted delivery will reduce exertion and shorten the second stage 1

Third Stage Management

• The third stage can be managed actively using a single dose of intramuscular oxytocin 1
• After delivery, a single IV dose of furosemide is commonly given to manage auto-transfusion from the lower limbs and contracted uterus 1

Critical Pitfalls to Avoid

• Do not rely on intrauterine pressure measurements to guide oxytocin dosing decisions 1
• Never use ergometrine or methylergonovine for uterine contraction management 1, 3
• Do not continue uterotonic agents in the presence of hypercontractility with fetal heart rate abnormalities 1
• Avoid supine positioning during labor as it may compromise venous return 1

Integration with Fetal Assessment

• CTG should be used in conjunction with umbilical artery Doppler assessment in fetal growth restriction 2
• Continuous CTG is associated with reduced rates of neonatal seizures but increased caesarean sections and instrumental vaginal births 4
• No single antenatal test has been shown to be superior, but all have high negative predictive values 2