What is the recommended management of preterm labor in pregnancy?

Management of Preterm Labor in Pregnancy

Administer antenatal corticosteroids between 24+0 and 34+0 weeks gestation, magnesium sulfate for neuroprotection before 32 weeks, and consider short-term tocolysis (nifedipine or indomethacin) to delay delivery 48-72 hours for steroid administration—antibiotics are only indicated for preterm premature rupture of membranes (PPROM), not for preterm labor with intact membranes. 1

Initial Diagnostic Assessment

• Perform transvaginal ultrasound for cervical length measurement as the most reliable tool to differentiate threatened from true preterm labor 1
• Complete digital cervical examination to assess dilation and effacement 1
• Evaluate for signs of infection, placental abruption, and fetal well-being 1
• Obtain fetal biometry, amniotic fluid volume assessment, and fetal Doppler waveform analysis at first diagnosis 1

Pharmacological Management Based on Gestational Age

Antenatal Corticosteroids (24+0 to 34+0 weeks)

• Administer corticosteroids between 24+0 and 34+0 weeks gestation to accelerate fetal lung maturity 1
• Corticosteroid exposure decreases death and neurodevelopmental impairment at 18-22 months for infants born at 23 weeks (83.4% vs 90.5%), 24 weeks (68.4% vs 80.3%), and 25 weeks (52.7% vs 67.9%) 2
• Reduces incidence of death, intraventricular hemorrhage, periventricular leukomalacia, and necrotizing enterocolitis in infants born between 23-25 weeks 2

Magnesium Sulfate for Neuroprotection (Before 32 weeks)

• Administer magnesium sulfate when delivery is anticipated before 32 weeks gestation for fetal neuroprotection 1
• Reduces incidence of cerebral palsy (relative risk 0.68; 95% CI 0.54-0.87) without increasing mortality (relative risk 1.04; 95% CI 0.92-1.17) when given before 30 weeks 2
• Magnesium sulfate prophylaxis is recommended if periviable delivery of a potentially viable infant is anticipated 2

Tocolytic Therapy

• Consider nifedipine or indomethacin as preferred tocolytic options to delay delivery 48-72 hours after 26 weeks gestation 1
• The primary purpose is to allow time for corticosteroid administration and in utero transfer to a facility with neonatal intensive care capabilities 2
• Important caveat: While tocolytics may delay delivery briefly, improvements in actual neonatal outcomes have not been consistently demonstrated 2
• A specific strong recommendation for or against tocolytic therapy cannot be made due to lack of consistent data showing improved newborn outcomes 2

Antibiotic Management: Critical Distinction

Preterm Labor with Intact Membranes

• Do NOT administer antibiotics for preterm labor with intact membranes 2
• Antibiotic treatment has shown no effect on pregnancy prolongation or improvement of newborn outcomes in this setting 2
• Amoxicillin-clavulanic acid may worsen long-term outcomes for offspring 2

Preterm Premature Rupture of Membranes (PPROM)

• Administer broad-spectrum antibiotics for PPROM ≥24 weeks (GRADE 1B recommendation) 1, 3
• Recommended regimen: IV ampicillin and erythromycin for 48 hours, followed by oral amoxicillin and erythromycin for 5 days (total 7-day course) 1, 3
• Azithromycin can replace erythromycin if unavailable 1, 3
• Avoid amoxicillin-clavulanic acid due to increased risk of necrotizing enterocolitis 1, 3
• Antibiotics prolong latency (median 90 hours vs 24 hours), reduce maternal infection including chorioamnionitis, and lower neonatal infectious morbidity (21% vs 35%) 3

Cervical Cerclage Considerations

• Consider emergency ("rescue") cerclage when fetal membranes are visible at or past the external cervical os at <24 weeks gestation 2, 1
• Placement requires absence of uterine contractions, PPROM, or contraindications such as labor or intraamniotic infection 2
• Observational and randomized studies show association with pregnancy prolongation, increased live births, and neonatal survival compared to no cerclage 2

Mode of Delivery

• Routine cesarean delivery is NOT recommended for periviable delivery alone 2
• Cesarean delivery has not been shown to decrease mortality or intraventricular hemorrhage after early preterm birth 2
• Delivery mode should be individualized, recognizing increased maternal morbidity with cesarean delivery 2
• Limited retrospective data provide some support for cesarean delivery in presence of malpresentation 2

Monitoring During Expectant Management (PPROM)

• Initial hospital observation to ensure stability without preterm labor, abruption, or infection 3
• Weekly outpatient visits for maternal vital signs, fetal heart rate, physical examination, and laboratory evaluation 1, 3
• Daily patient self-monitoring for temperature, vaginal bleeding, discolored or malodorous discharge, contractions, and abdominal pain 3
• Monitor for signs of chorioamnionitis: maternal fever ≥38°C, maternal tachycardia, uterine tenderness, fetal tachycardia, purulent cervical discharge 1, 4

Critical Pitfalls to Avoid

• Do not delay diagnosis of intraamniotic infection due to absence of maternal fever—clinical symptoms may be less overt at earlier gestational ages 1, 4, 3
• Never use amoxicillin-clavulanic acid in preterm labor or PPROM settings due to increased necrotizing enterocolitis risk 1, 4, 3
• Do not administer corticosteroids or magnesium sulfate before the gestational age when neonatal resuscitation would be pursued 3
• Avoid prolonged or repeated antibiotic courses beyond the standard 7-day regimen to optimize antibiotic stewardship 3
• Do not use tocolysis without concomitant corticosteroid administration when indicated 5
• Serial amnioinfusions and amniopatch are not recommended for routine care—two large trials showed no reduction in perinatal morbidity 3