What is the immediate management of a pregnant woman presenting with signs of preterm labor?

Immediate Management of Preterm Labor

Begin GBS prophylaxis immediately upon admission while simultaneously obtaining a vaginal-rectal swab for culture, then administer antenatal corticosteroids and initiate tocolytic therapy with nifedipine or indomethacin to delay delivery for 48-72 hours, allowing time for corticosteroid effect and maternal transfer to a tertiary care facility. 1, 2

Initial Assessment and GBS Management (First Priority)

Upon admission with signs of preterm labor before 37 weeks' gestation:

• Immediately obtain a vaginal-rectal swab for GBS culture unless a screen was performed within the preceding 5 weeks 3, 1, 4
• Start GBS prophylaxis immediately while awaiting culture results—do not wait for results before initiating treatment 3, 4
• Use penicillin G as first-line: 5 million units IV initially, then 2.5-3 million units IV every 4 hours until delivery 4
• If the patient enters true labor, continue GBS prophylaxis until delivery 3, 4
• If labor does not progress (false labor), discontinue GBS prophylaxis 3, 4

Critical pitfall to avoid: Never rely on oral antepartum antibiotic treatment for GBS—it is ineffective and does not prevent neonatal disease 4

Gestational Age-Specific Interventions

For 24-34 Weeks' Gestation (Standard Full Intervention)

Antenatal Corticosteroids:

• Administer to all women at risk of preterm delivery in this window 1, 2
• This is the only intervention proven to improve neonatal outcomes, including reduced mortality, intracranial hemorrhage, necrotizing enterocolitis, and infection 5

Tocolytic Therapy:

• Use nifedipine or indomethacin as first-line agents to delay delivery 48-72 hours 1, 2
• The goal is NOT to prevent preterm birth entirely, but to buy time for corticosteroids and maternal transfer 1, 2
• Indomethacin should be used with caution considering gestational age due to potential fetal effects 2
• Never combine nifedipine with magnesium sulfate—this causes uncontrolled hypotension and fetal compromise 2

Magnesium Sulfate for Neuroprotection:

• Administer if delivery is anticipated before 32 weeks' gestation 1, 2
• Reduces incidence of cerebral palsy in preterm infants 2, 5

For 35-36 Weeks' Gestation (Modified Approach)

• Continue GBS prophylaxis as outlined above 4
• Administer antenatal corticosteroids if delivery is anticipated and no prior course was given 4
• Do NOT use tocolytics at 35 weeks—evidence shows they may delay delivery briefly but have not consistently demonstrated improved neonatal outcomes 4
• Magnesium sulfate is NOT indicated at this gestational age (only <32 weeks) 4

Contraindications to Tocolysis

Do NOT attempt tocolysis when:

• Cervical dilation reaches 7 cm—prepare for imminent delivery instead 1
• Delivery would be beneficial for maternal or fetal indications 1
• Maternal fever ≥38.0°C or rupture of membranes ≥18 hours is present 4

Antibiotic Considerations Beyond GBS

For preterm labor with intact membranes:

• Do NOT give antibiotics beyond GBS prophylaxis—there is no benefit and potential risk exists 2
• Specifically avoid amoxicillin-clavulanic acid—it increases risk of necrotizing enterocolitis 2

For preterm premature rupture of membranes (PPROM):

• Antibiotics are strongly recommended after 24 weeks 2
• Use 7-day regimen: IV ampicillin and erythromycin for 48 hours, then oral amoxicillin and erythromycin for 5 additional days 2
• Azithromycin can substitute for erythromycin when unavailable 2

Maternal Transfer

• Arrange transfer to a tertiary care facility with neonatal intensive care capabilities during the 48-72 hour tocolytic window 1, 2
• In utero transfer is preferable to neonatal transfer 6

Special Fluid Management Consideration

• For patients with skeletal dysplasia or small stature, adjust IV fluid volumes to avoid fluid overload 1, 2
• Standard pre-loading volumes (e.g., 1 L before epidural) should be reduced accordingly 2

Mode of Delivery

• Do NOT perform routine cesarean delivery for preterm labor alone—cesarean is not indicated based on prematurity alone 4
• Obstetric indications for cesarean should follow standard criteria 4