Obstructed Labor

Obstructed vs prolonged labor

Prolonged labor means labor taking longer than expected, which can be from weak contractions, a baby in a less favorable position, or exhaustion. Many prolonged labors end in normal births with support or oxytocin. Obstructed labor means a physical block that contractions cannot overcome. Pushing harder does not help, and stronger contractions can be dangerous. See prolonged labor.

Causes

Related to the baby

• cephalopelvic disproportion (CPD): the head is too large for the pelvis
• abnormal position or presentation: brow presentation, some face presentations, shoulder presentation from a transverse lie, persistent occiput posterior in some cases
• large baby (macrosomia), more common with diabetes
• fetal abnormalities such as hydrocephalus or conjoined twins
• locked twins (rare)

Related to the mother

• small or contracted pelvis, from childhood malnutrition, rickets, young age, or previous pelvic fracture
• tumors such as fibroids or ovarian masses blocking the pelvis
• abnormalities of the cervix or vagina, including scarring or female genital cutting

Shoulder dystocia, where the head is born but the shoulders become stuck, is a related obstetric emergency.

Warning signs

During labor, signs that a skilled attendant looks for include:

• strong, regular contractions but no descent of the baby's head
• cervical dilation that stops progressing despite good contractions
• swelling of the cervix and a large swelling on the baby's scalp (caput) with overlapping skull bones (molding)
• a visible ring between the upper and lower uterus (Bandl's ring), a sign of impending rupture
• maternal exhaustion, dehydration, fever and a fast pulse
• fetal heart rate changes suggesting distress
• blood in the urine from bladder compression

A partograph or labor curve helps detect labor that is falling behind expected progress.

Complications

For the mother

• uterine rupture: life-threatening bleeding and loss of the baby
• postpartum hemorrhage
• infection of the uterus and sepsis
• obstetric fistula: prolonged pressure of the baby's head kills tissue between the vagina and bladder or rectum, leaving a hole that leaks urine or stool. It affects hundreds of thousands of women, mostly in low-resource settings, and is surgically repairable. See pelvic fistula.
• nerve injury causing foot drop
• death, in settings without emergency obstetric care

For the baby

• lack of oxygen (birth asphyxia) and brain injury
• infection
• stillbirth

Management

1. Recognize obstruction early, using careful monitoring of labor progress.
2. Resuscitate the mother: IV fluids, treat infection with antibiotics, insert a bladder catheter.
3. Stop oxytocin if running; it should not be used to push past an obstruction.
4. Deliver the baby: - Cesarean delivery is the usual treatment when the baby is alive. - Assisted vaginal birth (vacuum or forceps) is used only when the head is low enough and there is no true disproportion. - Symphysiotomy or other procedures are used rarely, mainly where cesarean is not available.
5. After birth: monitor for bleeding and infection, keep a catheter in for some time after a long obstructed labor to help prevent fistula, and follow up.

Prevention

• access to skilled birth attendants and facilities with emergency cesarean capability
• good antenatal care to identify risk factors such as a very large baby, abnormal presentation, or a history of pelvic injury
• delaying first pregnancy until physical maturity, and good childhood nutrition
• planning delivery in hospital for people with risk factors

Frequently asked questions

What is obstructed labor?

Obstructed labor occurs when the baby cannot pass through the birth canal despite strong contractions, because of a mismatch between the baby and the pelvis, an abnormal position or a blockage. It usually requires cesarean delivery.

What causes obstructed labor?

Common causes are cephalopelvic disproportion (the head is too large for the pelvis), abnormal fetal positions such as brow or transverse lie, a very large baby, a small or deformed pelvis, and pelvic tumors such as fibroids.

What are the complications of obstructed labor?

For the mother, complications include uterine rupture, severe bleeding, infection and obstetric fistula. For the baby, they include lack of oxygen, brain injury and stillbirth. Timely cesarean delivery prevents most of these.

How is obstructed labor different from failure to progress?

Failure to progress is a broad term for labor that is not advancing as expected, often from weak contractions, and may respond to oxytocin. Obstructed labor is a specific mechanical block that contractions cannot overcome and needs operative delivery.