Labor Pain

Definition

Labor pain is the visceral and somatic pain experienced during uterine contractions and cervical dilation, primarily due to physiological changes during labor.

Epidemiology

• Experienced by nearly all women during labor, though intensity varies.
• Pain perception influenced by parity, psychological factors, cultural beliefs, and labor duration.
• Primiparous women often report more intense pain compared to multiparous women.
• In low-resource settings, lack of pain relief options contributes to higher reported pain intensity.

Etiology

• Visceral pain from uterine contractions and cervical dilation (first stage of labor).
• Somatic pain from stretching of the pelvic floor, vagina, and perineum (second stage).
• Pain is mediated by uterine ischemia during contractions and compression of pelvic nerves.
• Psychological factors, anxiety, fear, and inadequate support may exacerbate perceived pain.

Pathophysiology

• First stage: pain transmitted via T10–L1 spinal nerves from cervical dilation and uterine contractions.
• Second stage: somatic pain transmitted via S2–S4 nerves from vagina, pelvic floor, and perineum.
• Contraction-induced ischemia contributes to visceral pain.
• Pain perception modulated by central nervous system pathways and endorphin release.
• Stress and anxiety increase sympathetic activity, heightening pain intensity.