Which of the following is NOT a recognized pathway to preterm labor?

• A. Infections and inflammation
• B. Maternal and fetal stress
• C. Bleeding
• D. Hypertension

Answer: (D)

The pathways that directly initiate spontaneous preterm labor are driven by infection/inflammation, maternal or fetal stress, and bleeding events. Infections and inflammation kick up cytokines and prostaglandins that stimulate uterine contractions and cervical ripening. Maternal or fetal stress activates the HPA axis and increases cortisol and prostaglandins, promoting labor as well. Bleeding, such as placental abruption or significant vaginal bleeding, can irritate the uterus and trigger contractions and cervical changes.

Hypertension, while it raises the risk of preterm birth, typically leads to early delivery for safety reasons (medical indications like placental insufficiency or preeclampsia) rather than directly triggering the labor process itself. So hypertension is not considered a direct pathway to spontaneous preterm labor.