Understanding Normal Spontaneous Vaginal Delivery: A Comprehensive Overview

Normal spontaneous vaginal delivery involves three stages:

1. Cervical Dilation and Effacement

• Dilation: Hormones (oxytocin) stimulate contractions → pressure on cervix → gradual opening.
• Effacement: Cervix thins (100% = fully thinned/expanded) as lower uterine segment stretches.

2. Fetal Descent and Expulsion

• Fully dilated → fetus descends via contractions and maternal pushing.
• Head engages pelvis, rotates (face toward mother's back).
• Expulsion through vagina completes birth.

3. Placental Delivery

• Placenta separates from uterine wall.
• Mild contractions expel placenta (third stage).

Duration varies by maternal condition, fetal size/position, contraction strength/coordination.