Preterm Birth
Prediction, Prevention, and Management
Evidence-Based Approach for MFM Practice
Prediction, Prevention, and Management
Preterm birth is not a single disease—
it is a final common pathway
for multiple biological processes
40–45%
25–30%
30–35%
From acute event →
trajectory beginning weeks to months earlier
Intervention works best before irreversibility
Recurrence: 15–30% after one
30–45% after two or more
The cornerstone of prediction
Risk modifier, not definitive predictor
Prior sPTB <37 weeks
History of LEEP/conization
Second-trimester loss
Universal screening in low-risk singleton pregnancies
Greatest value: negative predictive
Triage tool in symptomatic patients—not for screening
Indication: Singleton with prior sPTB <37 weeks Level A*
Indication: Singleton with CL <25 mm at 18–24 weeks Level A
Reduces PTB <33 weeks by ~40%
24 0/7 to 33 6/7 weeks Level A
Maximum benefit: 24 hours to 7 days after completion
34 0/7 to 36 6/7 weeks Level A
Based on ALPS trial (2016)
For fetal neuroprotection Level A
Reduces cerebral palsy and motor dysfunction by ~30%
Purpose: Allow time for steroids
and maternal transport
20 mg PO loading
Then 10–20 mg q4–6h
Limit to <32 weeks
<48 hours duration
Maximum duration: 48 hours
Reduces chorioamnionitis without increasing neonatal morbidity
Level A evidence (PPROMEXIL trials)
| Gestational Age | Survival |
|---|---|
| <28 weeks | 40–70% |
| 28–31 weeks | >90% |
| 32–33 weeks | >95% |
| 34–36 weeks | >98% |
Each additional week of gestation
significantly reduces morbidity and mortality
17-OHPC Efficacy
Evidence quality: previously Level A, now uncertain
Universal cervical length screening
in low-risk singleton pregnancies
Cost-effectiveness trials ongoing
Preterm birth is best addressed through
anticipation, not reaction