Normal Duration from Full Cervical Dilation to Delivery
The normal second stage of labor (from full cervical dilation to delivery) has a median duration of approximately 16 minutes in nulliparous women and 10 minutes in multiparous women. 1
Expected Timeframes by Parity
Nulliparous Women (First-Time Mothers)
- Median second stage duration: 16 minutes 1
- The second stage represents the period after the cervix reaches full dilation (typically 10 cm) until delivery of the infant 2
Multiparous Women (Previous Deliveries)
- Median second stage duration: approximately 10 minutes 1
- This represents 60-70% of the duration observed in nulliparous women 1
Important Clinical Context
Understanding Full Dilation
- Full cervical dilation occurs when the cervix is completely incorporated into the lower uterine segment, at which point it can no longer be palpated 2
- While this typically occurs at 10 cm, the actual dimension depends on fetal head diameter—it may be smaller in premature births and larger with fetal macrosomia or hydrocephalus 2
The Deceleration Phase Connection
- Complete cervical dilation and fetal descent are interdependent processes—full dilation generally will not occur unless fetal descent also takes place 2
- A prolonged deceleration phase (the terminal slowing of cervical dilation from approximately 8-10 cm) should raise suspicion for cephalopelvic disproportion (CPD) 2, 3
Critical Warning Signs
When to Suspect Complications
- If the deceleration phase is prolonged or fetal descent is delayed at full dilation, anticipate potential second stage abnormalities and shoulder dystocia risk if vaginal delivery proceeds 2, 3
- Prolonged second stage combined with prolonged deceleration phase increases shoulder dystocia risk 3
- These patterns suggest possible CPD, which should prompt consideration of cesarean delivery rather than prolonged attempts at vaginal delivery 4, 3
Clinical Pitfall to Avoid
- Do not assume that reaching "10 cm" automatically means the patient is ready for immediate delivery—assess for adequate fetal descent and watch for signs of CPD such as marked molding, deflexion, or asynclitism without descent 4