What are the indications for a preterm cesarean section?

Indications for Preterm Cesarean Section

Preterm cesarean section is indicated for severe maternal conditions threatening life, fetal compromise with irreversible causes, and specific obstetric emergencies that cannot be safely managed with vaginal delivery.

Absolute Maternal Indications

Life-threatening maternal conditions require immediate cesarean delivery regardless of gestational age:

• Severe cardiac conditions including pulmonary hypertension, significant aortopathy (aortic diameter >45 mm in Marfan syndrome), acute heart failure, or maternal cardiac instability mandate cesarean section 1, 2
• Maternal cardiac arrest requires delivery within 5 minutes of arrest onset to optimize both maternal resuscitation and fetal survival 1, 2
• Acute fatty liver of pregnancy (AFLP) or HELLP syndrome requires prompt cesarean delivery after stabilization of hypoglycemia, acid-base balance, and coagulopathy to improve maternal and perinatal outcomes 3, 1, 2
• Women on anticoagulation therapy (particularly warfarin) require cesarean section to minimize time off anticoagulation and reduce valve thrombosis risk 1, 2
• Anticipated difficult airway warrants cesarean section to avoid emergency general anesthesia 1, 2

Fetal Indications for Preterm Cesarean

Fetal compromise with irreversible causes requires immediate cesarean delivery:

• Fetal distress with irreversible causes including major placental abruption, fetal hemorrhage, and umbilical cord prolapse with sustained bradycardia 1, 2, 4
• Fetal growth restriction with abnormal Doppler studies (absent or reversed end-diastolic flow in umbilical artery) warrants cesarean section by 32-34 weeks 1, 2, 5
• Abnormal fetal surveillance including abnormal cardiotocography or ductus venosus Doppler requires cesarean delivery 1, 2
• Pathological cerebroplacental ratio at ≥37-38 weeks represents established fetal compromise requiring immediate delivery 5

Obstetric Emergency Indications

Specific obstetric emergencies necessitate preterm cesarean:

• Uterine rupture requires immediate cesarean delivery 4
• Complete placental abruption with maternal hemorrhage 4, 6
• Placenta previa with hemorrhage 4, 6
• Maternal trauma with hemorrhage 4

Infectious Disease Considerations

Certain maternal infections modify delivery planning:

• HIV-positive women with viral load >1,000 copies/mL near delivery require scheduled cesarean section at 38 completed weeks of gestation, regardless of antiretroviral therapy type 1, 2
• Hepatitis C with high viral load may warrant cesarean section to reduce vertical transmission risk, avoiding invasive procedures during labor 3, 1
• Hepatitis B in Asian HBeAg-positive women with high HBV DNA titre (>7 log₁₀ copies/ml) who have not received antiviral therapy during pregnancy 1

Common Medical Indications for Preterm Cesarean

Research evidence identifies the most frequent conditions necessitating medically indicated preterm birth:

• Preeclampsia is implicated in over half of all medically indicated preterm births and represents a major indication for cesarean delivery 6
• Small-for-gestational-age with concerning features 6
• Placental abruption (non-complete) with maternal or fetal compromise 6

These four conditions (preeclampsia, fetal distress, small-for-gestational-age, and placental abruption) are present in 53.2% of medically indicated preterm births and share a common pathway through ischemic placental disease 6.

Extremely Preterm Delivery (<28 weeks)

For extremely preterm gestations, cesarean section rates are high:

• Cesarean section rate is 75% for deliveries <28 weeks, with 60% performed on fetal indication 7
• Severe disease during pregnancy and delivery complications are the primary indications 7
• Non-isthmic (classical or vertical) incisions are performed in 20% of extremely preterm cases 7
• Evidence supports cesarean delivery even for extremely preterm infants when balancing surgical risks against infant benefits 7, 8

Critical Timing Considerations

Timing is paramount in emergency situations:

• Peripartum cesarean must occur within 5 minutes of maternal cardiac arrest onset to optimize outcomes 1, 2
• No maternal survival reported after 15 minutes of resuscitation, and no fetal survival after 30 minutes 1
• Cesarean should be initiated approximately 4 minutes after cardiac arrest to achieve delivery within 5 minutes 1

Important Caveats and Pitfalls

Avoid these common errors in preterm cesarean decision-making:

• Do not delay delivery in cases of established fetal compromise (e.g., pathological cerebroplacental ratio at term) waiting for "fetal maturity" 5
• Do not rely solely on biophysical profile or cardiotocography for surveillance in growth restriction 5
• Ensure immediate neonatal resuscitation capacity is available in all settings performing cesarean delivery 3
• Prepare for difficult surgery in extremely preterm cases, as one-third are considered technically difficult 7
• Avoid invasive procedures (internal monitoring, fetal scalp sampling, vacuum extraction) in women with hepatitis C and high viral load 3
• Regional anesthesia is strongly preferred over general anesthesia for most cesarean sections 1, 2

Preterm Labor Considerations

When a woman with planned cesarean presents in early labor:

• Perform cesarean section if cervical dilation is minimal and long labor is anticipated 1
• Allow vaginal delivery if labor is progressing rapidly 1
• The benefit of cesarean becomes unclear if membranes have been ruptured >4 hours 1

Antenatal Corticosteroids

Corticosteroids for fetal lung maturation should be considered:

• For all women presenting with preeclampsia at ≤34 weeks of gestation 3
• For women with gestational hypertension at ≤34 weeks only if delivery is considered within the next 7 days 3
• Not required at ≥38 weeks of gestation 5