What is the approach to managing uterine contractions at 31 weeks gestational age (GA)?

Management of Uterine Contractions at 31 Weeks Gestation

At 31 weeks gestation with uterine contractions, you must first determine if this represents true preterm labor requiring tocolysis or benign Braxton-Hicks contractions that can be managed expectantly—the distinction hinges on documented cervical change over time, not contraction frequency alone. 1

Initial Assessment and Risk Stratification

Evaluate cervical status through serial examinations:

• Perform an initial cervical exam documenting dilation, effacement, station, and consistency 1
• The critical diagnostic criterion is the rate of cervical dilation over time, not a specific centimeter threshold 1
• Re-examine after 1-2 hours of observation if contractions persist—progressive cervical change confirms preterm labor 1
• Contraction pattern alone is unreliable, as contractions do not consistently increase in intensity, frequency, or duration during the transition from latent to active phase 1

Assess fetal status and maternal stability:

• Continuous fetal heart rate monitoring is essential when evaluating preterm contractions 2
• Confirm intact membranes, as ruptured membranes changes management significantly 3
• Rule out placental abruption, preeclampsia, or other obstetric emergencies 4
• Position patient in left lateral position to ensure adequate venous return from the inferior vena cava 2

Criteria for Safe Discharge (Non-Labor Contractions)

If cervical examination shows no change after observation period, discharge is appropriate when:

• Fetal status is reassuring with normal monitoring and high presenting part 1
• Maternal condition is stable with intact membranes and no complications 1
• Contractions remain irregular without establishing a progressive pattern 1

Provide explicit return precautions:

• Return immediately for regular, painful contractions occurring every 3-5 minutes, lasting 45-60 seconds, for at least 1-2 hours 3
• Return for decreased fetal movement or absence of usual fetal activity 3
• Return for vaginal bleeding, rupture of membranes, or severe pain 3

Management of Confirmed Preterm Labor

When progressive cervical change confirms preterm labor at 31 weeks:

Tocolytic Therapy

• Nifedipine is the first-line tocolytic agent for acute management, though recent high-quality evidence questions its efficacy 5
• A 2021 placebo-controlled RCT found nifedipine did not significantly reduce preterm birth rates (52% vs 48%, RR 1.1) or delay delivery beyond 48 hours (78% vs 71%, RR 1.1) 5
• Despite limited efficacy data, nifedipine remains widely used: initial dose 20 mg orally, repeat after 90 minutes if contractions persist, then every 4 hours 5, 6
• Critical caveat: Nifedipine has paradoxical effects—it inhibits contractions in tissues with high regular activity but may increase contractions in tissues with low irregular activity through TRPC1 channel activation 7

Corticosteroids for Fetal Lung Maturation

• Administer betamethasone for fetal lung maturation at 31 weeks gestation (standard obstetric practice, though not explicitly cited in provided evidence)
• This is the primary goal of achieving 48-hour delay in delivery 5

Monitoring During Tocolysis

• Continuous electronic fetal monitoring when tocolytics are administered 2
• Monitor for hypercontractility (excessive frequency, duration, or intensity) that may compromise fetal oxygenation 2
• If hypercontractility develops, stop any uterotonic stimulation immediately 2

Common Pitfalls to Avoid

Do not initiate oxytocin at 31 weeks with contractions:

• Oxytocin is contraindicated in latent phase labor and has no role in preterm gestation 1, 3

Do not rely solely on contraction monitoring:

• Assess labor progress through cervical examination rather than contraction quantification alone 2
• External tocodynamometry times contractions but does not provide information about strength 8

Do not use ergometrine or methylergonovine:

• These agents are contraindicated for uterine contraction management in pregnancy 2

Do not ignore maternal reports of decreased fetal movement:

• Sudden decrease or cessation of fetal movements indicates severely compromised fetal status requiring immediate evaluation 3

Hemodynamic Considerations

Maintain optimal maternal positioning:

• Left lateral position prevents aortocaval compression and maintains placental perfusion 4, 2
• After 20 weeks gestation, patients should not lie supine during procedures or monitoring 4
• Systolic and diastolic blood pressure increase 15-25% and 10-15% respectively during uterine contractions 4

Pain management considerations:

• Paracetamol is the analgesic of choice for mild to moderate pain 4
• Short-term narcotic use is safe if paracetamol inadequate 4
• Avoid NSAIDs after 28 weeks as they may cause premature closure of fetal ductus arteriosus and oligohydramnios 4