What is the American College of Obstetricians and Gynecologists (ACOG) recommended management for a pregnant woman presenting with preterm labor?

Management of Preterm Labor According to ACOG

For pregnant women presenting with preterm labor, administer a single course of antenatal corticosteroids between 24 0/7 and 33 6/7 weeks of gestation if delivery is anticipated within 7 days, use tocolytics (preferably nifedipine or indomethacin) to delay delivery for 48-72 hours to allow corticosteroid administration and maternal transport, and give magnesium sulfate for fetal neuroprotection if delivery is expected before 32 weeks. 1, 2

Initial Diagnostic Assessment

Confirm true preterm labor versus threatened preterm labor through transvaginal ultrasound cervical length measurement, which is the most reliable diagnostic tool. 1, 3

• Document contraction frequency and duration, assess for infection signs, placental abruption, and fetal well-being 1, 3
• Perform digital cervical examination to assess dilation and effacement 1, 3
• If cervical length ≤2 cm or dilation ≥2 cm with regular contractions, diagnose as true preterm labor 3
• Obtain fetal biometry, amniotic fluid volume, and Doppler waveforms at initial diagnosis 1

Corticosteroid Administration

Betamethasone or dexamethasone should be given as a single course to all women between 24 0/7 and 33 6/7 weeks at risk of delivery within 7 days. 2, 1

• Consider corticosteroids starting at 23 0/7 weeks based on family decisions regarding resuscitation 2
• Betamethasone may be considered between 34 0/7 and 36 6/7 weeks for women at imminent delivery risk who have not received prior corticosteroids 2
• A single rescue course can be given if the prior course was administered >14 days ago, gestational age is <34 0/7 weeks, and delivery is anticipated within 7 days 2
• Rescue courses may be given as early as 7 days from the prior dose if clinically indicated 2
• Do not use regularly scheduled repeat courses or multiple courses (>2), as these are not recommended 4, 5

The evidence strongly supports corticosteroid use, with demonstrated reductions in neonatal mortality, respiratory distress syndrome, intracranial hemorrhage, necrotizing enterocolitis, and neonatal infection. 4, 6

Tocolytic Therapy

Use tocolytics to delay delivery for 48-72 hours after 26 weeks of gestation, prioritizing prostaglandin inhibitors (indomethacin) or calcium channel blockers (nifedipine). 1, 6

• The primary goal is to allow time for corticosteroid administration and maternal transport to a tertiary care facility 6
• Tocolytics do not improve long-term neonatal outcomes but provide critical time for interventions that do 6

Magnesium Sulfate for Neuroprotection

Administer magnesium sulfate when delivery is anticipated before 32 weeks of gestation for fetal neuroprotection. 1, 6

• Magnesium sulfate decreases the incidence of cerebral palsy in preterm infants 1, 6
• This intervention should be given in addition to, not instead of, corticosteroids 1

Management of Preterm Premature Rupture of Membranes (PPROM)

At ≥24 Weeks Gestation

Administer a 7-day course of latency antibiotics: IV ampicillin and erythromycin for 48 hours, followed by oral amoxicillin and erythromycin for 5 days (GRADE 1B). 1, 7

• Azithromycin can replace erythromycin if unavailable 1
• Never use amoxicillin-clavulanic acid (Augmentin), as it increases necrotizing enterocolitis risk in neonates 1, 7
• Antibiotics prolong latency, reduce maternal infection and chorioamnionitis, and decrease neonatal morbidity 1, 7
• Administer corticosteroids for PPROM before 32 weeks; efficacy at 32-33 weeks is unclear but may be beneficial if pulmonary immaturity is documented 4

At 20 0/7 to 23 6/7 Weeks (Periviable PPROM)

Offer individualized counseling about maternal and fetal risks of both abortion care and expectant management; all patients should be offered abortion care, and expectant management can be offered in the absence of contraindications. 8

• Antibiotics can be considered (GRADE 2C) but are not as strongly recommended as at ≥24 weeks 8, 1
• Do not administer antenatal corticosteroids or magnesium sulfate until the time when neonatal resuscitation would be considered appropriate by the healthcare team and desired by the patient 8, 1

Group B Streptococcus (GBS) Prophylaxis

Initiate GBS prophylaxis immediately with IV penicillin or ampicillin for all women with preterm delivery (<37 weeks) and ruptured membranes, regardless of known GBS colonization status. 7, 3

• Use cefazolin if penicillin-allergic without anaphylaxis risk 7
• Obtain vaginal-rectal GBS culture if not already done, but do not delay treatment pending results 7
• Discontinue antibiotics if the patient is determined not to be in true labor 3
• Intrapartum antibiotic prophylaxis provides 86-89% effectiveness in preventing early-onset neonatal sepsis 7

Cerclage Management

For emergency ("rescue") cerclage, consider placement only in the absence of uterine contractions or PPROM at <24 weeks gestation. 1

• After previable or periviable PPROM, either remove the cerclage or leave it in situ after discussing risks and benefits with the patient 8, 1

Monitoring for Complications

Monitor for signs of chorioamnionitis: maternal fever (≥38°C), maternal tachycardia, uterine tenderness, fetal tachycardia, and purulent cervical discharge. 1, 7

• Initial hospital observation is reasonable to ensure stability 1
• Daily temperature monitoring to screen for maternal fever 1
• Weekly outpatient visits for maternal vital signs, fetal heart rate, physical examination, and laboratory evaluation 1

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, 7
• Do not use amoxicillin-clavulanic acid, which increases necrotizing enterocolitis risk 1, 7
• Do not use serial amnioinfusions or amniopatch, as these are investigational and not recommended for routine care 8, 1
• Do not administer corticosteroids or magnesium sulfate before the time when neonatal resuscitation would be appropriate in periviable gestations 8, 1
• Do not use regularly scheduled repeat corticosteroid courses or multiple courses (>2) 4, 5
• Do not fail to administer antibiotics promptly when membrane rupture exceeds 6 hours in a preterm patient 7
• Do not perform cesarean section reflexively based on meconium alone without obstetric indication 7