Normal Labour Pre-term Labour Causes Etiology Tests Tm Summary
Membrane Activation ‣ 90% infection → From GU Infection (BV, C/G, rUTI, ‣ ) ‣ Abx, get ready for birth
Cervical Dilation Cervical Insufficiency 1) shorter <2.5 cm, 1.5 cm → 30-40% chance of PTL
  1. early effacement | ‣ | ‣ - short cervix

‣ - mechanical weakness | | Uterine Contraction | ↑ uterine stretch | ‣ , ‣, Intramural ‣, Uterine Anomalies (bicornuate, unicornuate) | ‣ | ‣ |

Maternal Causes

Fetal Causes

Risk Factors

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Previous spontaneous preterm birth

History Recurrence Risk
None 6–8%
1 prior ~15–16%
2 prior 20–30%
≥3 prior 30–40%+

Treatment / Complication

See Management

Category Agents Benefit Note
Tocolysis ‣ (‣) • delay labour (short-term only). Buy time for for steroids & transfer. Avoid in ‣
Corticosteroids ‣ • Induce Lung maturation
• ↓ IVH (intra-ventricular hemorrhage)
• ↓ ‣ 2 doses ≥48h before delivery. Some benefit even at 24h.
Magnesium Sulfate ‣ • ↓ risk of ‣ for fetals
• Prevent Seizure in ‣ Mothers Must be given to mother at delivery
Abx Early GBS Sw‣ • ↓ ‣ Prophylaxis ≥ 4hr antepartum